Jim Carters Truck Parts shows some of the parts in their catalog. Shown are the anti-droop springs for left and right door mechanisms, and the door strikers.

I did a quick and dirty search for a drawing of the door mechanism in 1946 Chevrolet Master Parts Catalog and didn’t find one for trucks. There is a drawing showing some limited information for cars, but those are a bit different from mechanisms used on trucks. My guess is posting a photo showing that one would lead to more confusion than would be helpful?

I’ll do some digging through my photos. I don’t recall having taken many photos of the dissection and rebuild of the door latch mechanisms. If I find anything useful, I’ll post it.

To get those fasteners loose, maybe soaking in a 50:50 mix of acetone and ATF will help?