I don't know if this will shed a little light or confuse the issue worse. It is my understanding that the balance of the unused AMU pistols were finally sold off from the factory to Gil Hebard, who owned a fair sized gun shop in Knoxville IL. and was a mainstay in the Bullseye community. An elderly acquaintance of mine, Frank Lewton, (now deceased), a long time gun show dealer purchased a large number of them from Gil and sold them off. He also had a very large quantity of the 38 AMU ammo. After his death about 3-4 years ago I was at an auction which included the remains of Frank Lewton's estate, and there was still about 40 to 50 boxes of the 38 AMU ammo which sold out at the auction for about $5 a box.
Frank had been a real character and sold guns from his home in Quincy, IL for many years as well as attending many Gun Shows. Some time in the 70's, when he tired of the GCA68 requirements on FFL's he changed to buying and selling diamonds and jewelry as he would say "There's no S/N's on diamonds". Quite a nice character, he was in his upper 90's when he passed.
I still have a book written by Gil Hebard, "The Pistol Shooters Treasury". 2nd edition published in 1973. It has articles written by such notables as:
Bill Joyner, Bill Blakenship, Bill Taney, Paul Weston, Harry Reeves, Joe White, Lew Weinstein, Dick Shockey, Jim Clark, CCI Tech Staff, and the US Army Advamced Marksmanship Unit. It contains a lot of marksmanship information you seldom see today. Tips on how and why for accurate competition shooting. If you ever see one in a used book store pick it up you won't be disappointed.