I have an early 1962 model 36. An S&W letter says it was shipped to the NYPD in that year. The serial number is stamped on the butt of the frame and on the inside of the RH stock, but no where else. Shouldn't it be stamped on the barrel and the cylinder? The frame has no stamps on it going back to S&W for repair, although I believe it did go back. Should there be other places with the serial stamped?