Actually, the armorer probably would have stamped the new disk, perhaps because he determined the original stock was no longer usable or else replaced the barrel. If the stock had been replaced, the SN on the butt plate would either be stamped matching or else lined out and the proper SN marked. A mismatching stock is likely a civilian effort.
I did a quick check just now, and both original and repro stock disks are currently available on ebay. Without documentation, I'd be more inclined to believe a disk without punch marks to be the product of an enterprising owner who found one online
I did a quick check just now, and both original and repro stock disks are currently available on ebay. Without documentation, I'd be more inclined to believe a disk without punch marks to be the product of an enterprising owner who found one online