Exterior Trim Question

[Black77USS]

My 77 911S only has 40K miles on it. It spent most of its life garaged until its owner died. It sat out in the Georgia weather at a shop for approximately three years before I bought it from the PO's estate.

It is black and will need a paint job due to the paint separating from the galvanized body in various places. Never any body damage though.

The trim is a dull silver for the most part and in excellent condition with the exception of a few areas that seem to have changed color. Part of the passenger side window trim and the hub caps are a medium to dark bronze/brown. I need to know what caused the silver to bronze change?!?!?

Is the trim painted or anodized? Is there an easy fix to get all of the trim matching again? The wheels are the same silver and pretty good condition. Thanks in advance for any guidance here!