I think perhaps they could be lacquered. I have a set of the earlier "MA" and I would guess these may have a clear lacquer or some such treatment... but ae not anodized.
Any of the anodized rims I own or have seen, have either a "machined" brake track, or are left with the sides completely anodized as well. Mine are not machined and do not have anodized sides. With a sprayed or brished on clear lacquer, you could easily treat only the exposed centers of the rims but leave the sides untreated for better braking performance - and without having to later sand or machine those flats.
Bob Hanson, Albuquerque, New Mexico, USA