no doubt some of the rods use a flattened finish coat, but epoxy primers [2 part, high build or thin build] are definitely waterproof and can be used for top coats - my 58 did fine for a couple years with the front epoxy primered until all the body work was ready for paint - and epoxy primer can be tinted to some extent
the primer-surfacers, etching primers, and the usual lacquer rattle can primers aren't waterproof
Bill
