Originally Posted by OldChief

I'd say your revolver dates to 1977. The Engineering or Production change 10-7 and 10-8 both came in 1977. I was unable to find the ABS prefix serial number. I'm sure there's someone more knowledgeable that I on the forum who will come up with the ABS numbers. Now an engineering change in 82 eliminated the pinned barrel and began the 3-letter serial number prefix but I believe this would have been 5 years after the model 10-8 came about. Now I'm really confused.