CO2 lasers don’t etch metal, but the laser materials page says it will vaporize the anodize for an etch-like finish. (Obviously if it isn’t anodized it won’t work).
Metaza is a good alternative, assuming you can limit your etching/engraving to the flat section.
EDIT: Here is a Show and Tell post with examples. Scroll past the colored dye-sub images until you get to the Metaza examples.