"There is the Ruger Model 77 and the model 77 Mark II. The Ruger 77 (with the tang safety) came in two basic action styles, the shorter action, which has the bases for Ruger rings integral with the action, and the "round top" longer action, which has the bases attached by screws. I had one of the round tops in .30-06 back in the early 80s. There were lots of variations in bbl and stocks, but the basic actions were either one type or the other.
I think there was a later version of the 77 where the "round top" was replaced with the integral bases, but I am not sure. I do know the guns made during the 70s and 80s were either "standard" or "round top" actions."
IIRC, the round top was a somewhat limited edition in only a few calibers. Most of the tang safety Ruger M77s used the Ruger rings. In fact, I've only seen two Ruger 77 round top rifles at gun shows and they commanded a premium price.
COMPROMISE IS NOT AN OPTION!