Correct finish for 1972 tail light housing

I'm restoring my tail lights, which are essentially a matted ball of rust and multiple layers of paint and underseal from which no light emitted.

The interior and exterior original finishes were over-sprayed multiple times, so I stripped off all the paint and rust in my media blaster. I now have 2 bare metal housings to refinish. What should they be painted or coated with, inside and out?

Did they have some kind reflective finish inside? (Mine were badly brush painted white inside)

One of my lights is missing a parabolic reflector on the brake light, can these be obtained from anywhere?

My observations have been that the reflective surfaces were white for Euro cars, and some type of thin chrome-like coating for the US (I have both types). The outside of the housing has a thin layer of silver paint, but given that it is exposed to the abuse of the rear wheel spray, that little bit of protection doesn't last too long and the pot metal begins to corrode. The metal covers on the back appear to be clear zinc galvanized.

I tried an experiment with a pair of mine recently and used silver POR15 on the outside of the housings, and re-plated then clear powder coated the metal covers. I'm curious to see how long it lasts.