two34s, welcome to the 'Bolt! I'd say probably the best place to check would be Mar-K. I don't for sure if they have the plans that far back, but they are a leader in repro bed components. There's a link to them on both the Links page and in the Making A Stovebolt Bed section.
If you can, perhaps a few pix of the bed and/or the parts in question might help. Actaully, some pix of the truck overall would be really cool, don't see too many of them from that era anymore.
