One of the Archive threads, there's a few, addressed this. General opinion:
Pop-up spring black phosphate
Hood latch & secondary catch a brownish zinc.
Hood striker body color.
Hood release lever brown zinc.
Trunk latch clear zinc (silver color).
Trunk striker may have varied by plant, either clear zinc or painted.
Attaching bolts to plated items black phosphate.
No painted latches or levers on anything I can think of.
Actually, different parts of the latches were different colors/plating.

Scott Smith's observations differ:
Moparts Forums › topics › factory-finishes-for-70-340-duster-parts-help