Replacing Upper Door Jamb on Cab

[grandfisher]

I have a 76 crew cab that I'd like to start body work this spring. The truck is very rust-free with the exception of the upper door jamb on the cab. There was a sun visor installed on the truck and apparently it leaked for many years. My question is, what are my options for replacing/repairing this part of the cab? I've looked for replacement panels but I can't find any. I do have some cabs lying around that I could cut the pieces out of but I'd rather not ruin a cab if I don't have to. Any advice would be much appreciated.