I don't know what year they started putting them on but Airstream started using the Alcoa Dura-Bright wheels that supposedly don't need polishing. You can tell by the P/N which is stamped on the wheel and is visible on the outside rear dual. There will be DB at the end of the P/N.
The Alcoa website has cleaning instructions and it doesn't sound like they are clear-coated but somehow the alloy has something in it to prevent oxidation. You can also probably tell by using metal polish in a small area and if it comes off black on the rag, then they aren't Dura-Bright. But the P/N is the best way to tell.
Recommend checking the Alcoa website to be sure.
Glass half full or half empty to an engineer is simply a glass that was over designed.
PM me for sale info on my 2011. SOLD!