pro-compe was a mid-level SunTour grade in the early 80's (and probably late 70's but I don't know). Some of the nicely equipped bike shops would have all the various cogs available so you could get custom ratios. I had a 14-21 and 14-23 (both custom) on my bike. The silver was simply a nicer finish, sort of "deluxe".

The "high end" stuff was Regina, Maillard (I think they had a half alloy freewheel), and the piece de resistance, Campy's all alloy freewheel.

cdr