The wood was not painted, they used a mixture of linseed oil and lamp black or stove black, I don't recall which.

When I replaced the bedwood on my '54, I followed the study MAR-K conducted and did the POR-15 and Behr paint method on southern yellow pine. My truck bed is exposed to the Florida elements every day 24/7 and I do not plan on installing a bed cover. Its been nearly a year and it looks like the day it was installed.

MAR-K is one of the links here or do a google search for MAR-K. Very insteresting study. I'm thankful for their contribution.

Good luck.