Roy, Very good point. I think you hit the nail on the head. If the receiver, and if it has sideplates were originally case-hardened, had the case colors, and the colors wore off, the case-hardening would still be there. Now originally, the depth of the case-hardening was .002-.005. Re case-hardening the piece would definetly do something to the metal, what I don't know. Maybe there is a metallurgist out there that can add some light to the picture.

David