Don, it seems to me that the possible reason for the numbering would be down the line an armorer could disassemble several guns for cleaning, etc. and as long as he first checked to see none were of the same last two digits he could be confident that reassembling them would not lead to a nightmare of problems. So if he had spares and discovered that one needed a new part he could just stamp one of the spares with the matching last two. THat part may not perfectly match the shape/contour/ whatever of the original but it was part of the legitimate process for fielding the weapons. So one could have in your hands a pistol that looked in every way the same but one was "legit" (at least in my mind, perhaps not in the mind of a very serious collector) and the other was created decades later by someone in an attempt to deceive.
|