there you go, this tells us they were bought 'later' or as an "extra" at the time of purchase at the shop, if the shop puts the gun out for display (sale)with something 'else',(options) they just may have kept or put on some other gun,,,,BUT remember, back then as I noted to the price marks, "parts, extras.." were fairly cheap, during that era, or time period..it was later, when no one was making them so not readily available, they became harder to get, harder to find, and now "costly", even if they are NOT "factory"........nice find, and even BETTER that you are getting the grips too.........
by the way, is that a 5 -digit number ? or 6 digit ? cause if its in the 14,xxx range , it would have been a "flatgate", and that is NOT a Premiere loading gate in the picture......inquiring minds, "need to know" :wink: