I'm up to five sets now. The most recent are what was described on ebay as 1980's police car caps. Far left in the picture. I paid 5 bucks plus shipping for 6 of them. They were pretty battered, but cleaned up well. As of yet the only caps that I have sanded on are the ones pictured on the truck. My dent smoothing skills are becoming much better.
I'm about done shopping for caps. I would however like to find a set of 60's COPO caps, and a decent set of 67/68 style Stainless steel truck caps.
This is what they looked like when I got them.