Gents,
I believe that replacement trim ring is simply clear anodized aluminum, just like some of the body trim.
On Saturday, I went to the Judging Class held by Pete Lesler in anticipation of Gemutlekeit. Mike Webster brought his "new" 1966 Eurospec 230SL, done by Passarelli at RanchoMerced. This is the car I judged as practice.
One thing I noticed (and which he lost an imaginary point for) was that the ignition switch trim ring was wrong; it was way too big and thus didn't fit properly. Because of this, it was sitting at an angle and couldn't be flush with the surface of the dash. There was no way to correct it with that part; simply too big.
Speaking of that car, which was indeed beautiful, was that even this professional restoration had quite a few inconsistencies. Mike got a free laundry list of things he can easily change if he wants to show it, and other things somewhat more expensive to change "the next time around". Perhaps the most bizarre addition was a logo spelling out Mercedes Benz immediately behind the right wheel low on the fender. Mike said its Passarelli's "trademark".
Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored