Thanks 1968RSZ28 for the link- From that information, it looks like unless these mated hubs/rotors were index marked prior to disassembly, they could be out of balance when assembled again. Starting to look like more time and trouble than these things are worth. LOL
You know, it's really not that much different than late-model rotors - only they aren't bolted together, they float on the hubs in most cases. True, they are balanced individually, but when you install a new set of rotors, aren't you really seeing the same chance for imbalance with them changing the balance point of the original set ?