Well I just rolled back to the house from the Spring Fling. I guess if a guy is looking for C body parts you might as well try somewhere else. I went there with high hopes of finding the regulator rebuild kit for the rear quarter window regulators. There were two (parts) vendors there and both looked at me like I had 3 eyes when I said 1966 300. At least they didn't point and laugh. As far as the swap meet part of the event, no help there either but they did have a lot of "cool" parts a guy might need.
About 300 miles round trip with only found a trunk weather strip that I could have gotten on-line, had to pay full retail price of course. If anyone knows of a vendor for the regulator rebuild kits, I'll owe you a beer if we ever meet.