4 Rush, Is the 1581 that is stamped under the grip, stamped on the right side of the back strap area of the grip frame and not on the butt area under the grip? I have examined about 1/2 doz. 3rd model Russians in my collection, both contract guns and commercial models, and some of the commercial models have reject parts from the Russian contract guns. Some of the Russian contract guns have no serial number stamped on the butt, but it is stamped on the grip frame back strap under the grip. It is my opinion that the J or JJ and the Y stamps are S&W inspector stamps, and the gun you have is partially made of parts from rejected contract guns and that the 4924 could be part of a 5 digit serial number, however the size of the number is larger than numbers stamped by S&W on commercial guns. The number has been defaced by some one in the past. It was not worn off by a lanyard swivel. The 1581 number is the original contract gun serial number and the barrel rib has had the cyrillic stamping removed by the factory and the commerial stamping applied. Measure the height of the barrel and rib about an inch behind the front sight. An original Russia gun with cyrillic markings will measure about .903 inches at that point. If the cyrillic stampings have been removed and the commercial stamping applied, the measurement will be little less than .9 inches. There is a lot of confusion about the Russian contract guns, the rejects and the commercial models. Stampings were always changing, as well as inspectors marks and their locations. Guns are always showing, such as this one, that are real puzzles, however by comparison with known examples. The Russian inspectors were extremely fussy arout the guns. If any of the guns shipped to Russia by S&W that had passed the inspection of General Gorloff and his staff and later failed to function when tested in Russia, it was curtains for the General when he returned home. The Czar did not tolerate any errors. Gorloff personally saw to the firing of 10,000 rounds of .44 Russian ammo. out of every 100,000 he ordered from UMC. If one round misfired, the entire lot of 100,000 rounds was rejected, as one misfire of a delived round in Russia meant the chopping block for Gorloff's head. Whatever your gun is, it's a bit of S&W history from a period when keeping the Russians happy ( they paid in gold coin!) was S&Ws ticket to economic survival. Too bad the US doesn't use that system for some of our military contracts! Hope this helps! Ed.