I guess I missed where you determined if your truck was Chevy or GMC?? I own a '42 Chevy 1-1/2 ton G506 army truck, and what I'd offer is that as a truck built for the military, it has MANY civilian parts, and assemblies. That said, it also has MANY that are unique to the military models. When I first looked at your Photobucket page, I thought it was likely military... You need to find yourself a set of manuals so you know how it was when original.
You can see some info about my truck here:
ChevyG506.shutterfly.com