ok I think I figured this out for you. I have done a couple 47-66 trucks so I know the bed strips for those have a "double hole" at the front of the strips, the very front one goes to the front bed panel and the one just a couple inches back gets the washer on the bottom and holds just the wood.
but looking at the 3 38-46 beds I have in the back yard, one has original wood, and I can see that the strips are like yours, only one hole at the very front. there are bolts through the WOOD only that go through to the front panel lip, as seen here:
you can see that the bolts for the front panel are in the center of the boards, not in the strips. I am pretty sure this is original wood in this one bed and the other beds dont have any wood but the front panel bolts are in the same spot.
I took another picture from the top side but this bed had a sheet of metal on top of the wood and there is a welded angle blocking your view of the bolts, but you can see the split in one board caused by the bolt.
