The number you listed for the 10-5 is the assembly number, which is arbitrary and basically meaningless. The serial number of a Model 10 is found on the bottom of the grip frame. It will be a 6-digit number preceded by a "C" or a "D".
The Model 19 is 1976 production.
Thanks, that is in fact the only "serial" number on it. I haven't seen it, he sent me a pic but it didn't come out so I asked for another.
Edit: Here are the pics he sent me. The same number appears in both places and there is no number on the bottom of the grip.