Hey Harry,
I'm definitely no expert, but my wells were painted body color from the factory...bolts and all. Someone had added undercoating at a later date...from what I read the undercoating was never factory installed.
For my restoration, I have blasted, used an etching primer, and will then spray with a modern base/urethane clear. The result will be a million times more chip resistant than the original single color without primer. I know many don't like the clear, as it detracts from the originality...but hey...it lasts decades longer!
There are chip resistant paints that will give your wheel wells the original look and also be chip resistant, if you are concerned about rocks where you live. They are thick, so not appropriate for anything but the wells.
John