Let's put this into perspective...My bedwood was original to the truck, only 2 of the 9 boards rotted through after 50 years of no care at all. If you show, you want to do what they did at the factory, if you haul stuff, if it never is going to see the inside of a garage, I'm sure you want weather protection. The summer I stepped through a bedboard while at the recycling facility I decided that after 52 years the old girl deserved a new bed.
I used found wood from a construction site (I don't call 'dumpster diving' stealing) and milled it on my home table saw to the correct dimensions for a '49 bed. I then painted the underside with a coat of Kilz as primer, then 2 coats of white housepaint. I wanted increased visibility when working underneath. I re-used the metal strips and replaced all the bolts with galvanized. I made my own bed blocks and protected them with a couple coats of housepaint. On the topside it actually came out too nice for me, I just used a pint of satin polyurethane until the can ran out.
Cosmo\'s eight dollar bed wood