63ChevyNova,
The inliner folks do know their cams. "If" you pull the head to do the valve springs, which I would recommend, it might allow you to take a peek inside the engine. If there was any doubt as to the state of the head, a automotive machine shop could be sought out to install the springs, and while there, the head could be checked for guides and maybe valve seat condition.
The previous owner might have taken liberties with the term "rebuilt". I think the new cam would require NEW lifters, as opposed to good used lifters. It sounds like you are going to do this project right, so take a little time and make the best decisions.
Stuart
