I see that Griffin and Howe has record of this gun so I will also send for their information. If the stock came from a different gun it would have a different serial number stamped into the wood. The existing (correct) serial number isn't stamped over any other numbers. I would also think that if someone restocked the gun, they might have stamped it with the correct serial number but why stamp this Pigeon Grade gun with the M? I am thinking it is a factory restock. Did LC Smith stamp an R when they restocked a gun? I have a Parker that is stamped that way.