Preface
The following is a short summary which I put together from several internet informational sources, forum threads, and my personal observations. As I am not a professional historian, the presentation may contain some errors or omissions of important facts. But the hope is that it will at least be entertaining and thought provoking for collectors of European pistols. Observations, comments and corrections are assuredly welcome.
I chose the Axis Pistols, 1933-1945, German: Foreign Mfg. Pistols and Holsters forum for the reasons that the topics which cover the FN M1922 are most commonly found in this forum, and I also believe that my Yugoslavian Contract pistol may have been captured by the Germans in WWII, and then brought to the U.S. in the post-war period. Just a hunch.

Background

From its inception in the late 1880's, Fabrique Nationale of Herstal, Belgium had become a significant producer of small arms. Teaming with designer, John M. Browning, FN rapidly advanced in modern pistol technology and production with new models/variants being introduced in 1899, 1900, 1903, 1907, and 1910.
One pistol in particular - it was the infamous FN M1910 with serial number 19074 which was allegedly used by the Young Bosnian member, Gavrilo Princip, to assassinate Archduke Franz Ferdinand of Austria in Sarajevo in June 1914. This event is most commonly cited as the tipping point to roll the world into the chasm of The Great War.
Two good reference links:
http://www.cruffler.com/historic-may01.html
https://en.wikipedia.org/wiki/FN_Model_1910
Of course, the best Fabrique Nationale pistol reference is the book by Anthony Vanderlinden, FN Browning Pistols, Side-Arms that Shaped World History.
http://www.fn-browning.com/new_page_1.htm

FN Model 1910/1922 Development
Through the two Balkan Wars and WWI, the number of small arms were greatly depleted in Serbia. And in the early 1920's the newly formed conglomerate country of The Kingdom of Serbs, Croats and Slovenes (later, Kingdom of Yugoslavia) sought to re-outfit its army, but with a more significant pistol than the FN M1910 in terms of barrel length and capacity. Fabrique Nationale was chosen to be the producer.
To defer the cost of retooling for a completely new gun design, the Browning FN M1910 in 9m/m kurz was chosen as the base. As with the original M1910 design, the blowback/striker-fired pistol would employ three safety mechanisms - grip, thumb and released magazine.
For the upgraded design, the major changes were:
1. The barrel was lengthened from 88mm to 113mm, which required the introduction of an interlocking extension collar to the front of the main slide. This provided for a greater sight radius.
2. The grip frame and magazine height were extended to allow for an eight vs. six round capacity.
3. A lanyard ring was also added to the lower left rear frame.
The design changes to the FN M1910 were finalized in 1922 and the new pistol designation became known as the FN Model 1910/1922, also referred to as the FN M1922, FN 10/22, or FN1922. In early 1923, Yugoslavia initially contracted for 60,000 units, with the final orders being filled into the 1930's, and as many as 70,000-plus delivered.
Wikipedia file photo of FN Model 1910
Yugoslavian Contract FN Model 1922
Barrel/slide extension
Lanyard ring
Grip/mag increased height and capacity
Field stripped
The relatively simple and reliable design of the Yugoslavian M1922 became a great selling tool for Fabrique Nationale. It was offered in 9m/m kurz (9mm short, 9 X 17mm Browning, .380 acp) or in 7.65m/m (7.65 X 17mm Browning, .32 acp). The model began to spread throughout Europe in the 1920's and 1930's, with military, police, private security and commercial contracts going out to Holland, Turkey, Greece, France, Romania, Finland and Denmark. During war-time occupation of Belgium, Germany produced more M1922 pistols than any other model at FN (1940 - 1944). And post-war contracts continued up through the early 1980's to countries such as West Germany and France.
Small arms were once again depleted from the Balkan Region during the occupation of Yugoslavia in WWII, with a large number of its FN M1922 pistols being captured and pressed into German service. Other country's contract versions of the FN 1922, as well as those produced under Nazi occupation at the FN factory, were already popular with German officers, and the Luftwaffe in particular.
Identification
Today's featured pistol is the most commonly seen version of the Yugoslavian Contract FN M1922, and has the Serbian Cyrillic stamp on the right side slide of Војно државни, for Army (or Military) State. Another version is rarely encountered and is stamped as официрски, for Officer's issue. The Yugoslavian crest is stamped into the top forward area of the main slide.
A fine example of the 'Officer' stamped slide may be viewed here:
https://luger.gunboards.com/showthread.php?40038-Yugoslavian-Officers-1922-rig&highlight=yugoslavian
Following WWII, a great many FN pistols came to the US with our returning service members. The Yugoslavian Contract pistols were among them. They are not rare in the States, but are less commonly encountered than those FN1922 pistols of other major contract countries.

Picture Details and Observations
My example is in pretty decent overall shape at 90-plus % of finish, with light freckling and grip thinning, some minor edge/holster wear, and minor scattered pitting on top of the slide. The signature rust bluing on these FN 1922 pistols is very attractive, and the same specimen can range in appearance from a near royal blue in natural light, to a dark slate gray in artificial or low light.
Interesting to note that the two-line left side slide is stamped with 'FABRIQUE NATIONALE D'ARMES DE GUERRE S.A. HERSTAL BELGIQUE' and 'BROWNING'S PATENT DEPOSE'. All of my slides from other M1922 contracts are marked similar, but absent of the 'S.A.' (for Société Anonyme, or Incorporated Company) which precedes the Herstal Belgique. All of the pictures which I can find for the Yugoslavian Contract pistols below the approximate serial of 55,000 also are devoid of the S.A.
The only other Yugoslavian Contract example which I can locate on the web which has the same slide stamping as mine is also serial numbered in the 66,000 range. It can be viewed in the following thread, p.3.
https://luger.gunboards.com/showthread.php?29615-Browning-10-22-for-the-Army-of-the-Kingdom-of-Yugoslavia&highlight=yugoslavian
The Lion over P.V stamp is the nitro powder proof, and the Star over Y stamp identifies the proof controller, Chesnoy Léon.
Belgian Proof Mark reference: http://damascus-barrels.com/Belgian_All_Proofmarks.html