Bill wit the Red58, if it's really a '52 door I don't think it's "ElectroDeposition Primer". Correct me if I'm wrong but I believe that was first introduced by duPont in 1963.
Bill_B, what's alpo prime, I've never heard the term?
I had a thin black primer under the original interior paint on my '50 garnish moldings. It wet sanded just like any other cured paint with 220 paper and I finished it with wet 3m Scotchbright pads before I conditioned the bare steel.
Denny Graham
Sandwich, IL