You remember correctly. They were 65s. After the L-Frame came out in the early '80s OHP replaced the 65s with 681s.
I'm with you on the 3 inch K-Frame round butts. It's the slickest carry revolver ever made provided you didn't wear it out shooting too many magnums. In 1985 I had a S&W 547 3 inch round butt in 9mm that I still punish myself for trading off.
WOW, nice thread resurrection!