I don't know that I've seen any that I could absolutly say had black paint. I think there were some, and if it was paint, I'd expect it to be a flat/satin laquer. That would explain the paint flaking as the paint wouldn't stick well to the tank. Most I've seen have undercoat, even if the car doesn't. Kinda makes me wonder if there were three phases. Nothing, blk, then undercoat, due to process changes.
