Gran Compe is the fancy version of Dia Compe. Like Lincoln instead of Ford. They are simply the deluxe version with better finish and some upgraded bits and pieces -- for the most part. The short reach Gran Compe 450 center pulls were Gran Compe only. For that matter all but the GC 450 were license built versions of Weinmann CP brakes. As someone noted, even the Weinmann labeled brakes were made in various places.
I'm not sure if "G-Type" was an earlier version of Gran Compe, or if it meant braze on. A bit before my time. Anyone know?