Factory fastener finishes

What would have been the factory finish for the various nut and bolts used to hold these jeeps together. Mine is a '57. Mine are mainly rusty or coated in filth and it's hard to determine what the original finish was. Some look zinc or galvanized others are black. I know this is a vague question because there are so many fasteners and so many details that would have changed during production.

 

mine are all gonna be black. dunno the original finish, but the ones on mine that still have some finish left look to have been black.

 

I would guess they were bright plated, and the plating has since failed. Unlikely they are galvanized, as this is a premium coating usually reserved for continued outdoor exposure.

Some hardware could be black oxide finish, but this is inferior to bright plating for weather resistance. Black oxide hardware will even rust in the bin if kept in a humid environment.

From some quick online reading, it looks like modern bright plated bolts are zinc coated, though tin or cadmium is also possible. I don't think the type of bright plating really matters, as Jeep certainly used whatever was least expensive at the time.

 

This brings up another question. Were the sub assemblies, i.e. front end, painted after assembly, resulting in everything being a black chassis color, covering the original finish on the bolts. The pictures in the FSM I have don't show a lot of detail, but everything on certain assemblies all look the same color.

Jerry