Many of these items were cad plated or zinc barrel plated, in other words - not shiny. In the 60s, plating standards were not as rigid as today. What the car manufacturers wanted was rust protection, not a reflective surface.
Radiator cap
Radiator hose wire straps
Jack handle
Radio mounting bracket
Real tail light housings
Trunk catch, not latch
Door internal parts
Flasher mounting bracket
Ash tray body and slide
Dull zinc became available as an inexpensive process about 5 years ago.
If you bead blast prior to dull zinc plating (and don't touch the items), you will get good results replicating the zinc process of the 60s. I've had to replate a few items in dull zinc that were too bright.
Jim