EDP in the 60s is a possibility (and is the time period in HRJ's start to this thread), but this discussion had moved into the 40s & 50s (A-D years). Red-oxide (leaded) paints was of course available prior to the 60s but EDP supposedly was not used until after the A-D years.
As Denny posted in another recent message about the black paint/primer used on A-D trucks, it is hard as heck to remove it, but it is not very good at rust prevention (especially if scratched).
