No finish on the brake arms would be my guess. The bolts used to attach would have also been what the supplier put on them. If you are looking to preserve the look of new, a rattle can of clear coat may keep them looking good, but dust, road grime and grease residue is the only coating they received.
As far as other hardware being plated, I found little on tear down on the 46 that was plated. The little nut and bolts on the E-brake handle are the only ones I can think of.
