I just checked mine. They are all at minimum needing polished. I have one that is straight but needs polishing. The rest all have little dings and scratches
Adam got it right, GM used a cheaper line of stainless and flash chrome them for pertection. Like the bumpers from the factory, they didn't have a mirror finish.
Atleast they were/are stainless, Chevrolet used an aluminum or some combination light weight crap on the Chevelle's that stood no chance of surviving.....
I have an NOS set of 68 wheel well trim and they are not shiny, kind of a dull shine. The trim rings on my wheels were also flash chromed according to the company that polished them quite a few years ago.