10-8s were made from 1977 to 1988. Those other numbers aren't the serial number - you'll find that on the butt (bottom of the grip frame) and it might be covered up by oversize grips that you'll need to remove. It should be a 7-digit alphanumeric with a "D" in it and the rest numbers, or starting with three letters, followed by 4 numbers. If you post that, we can tell you the year.
NRA Benefactor Life Member
Pemigewasset Valley Fish & Game Club