Sure. I've never had anyone say that they couldn't do it because the muffler was too dirty. How it holds up depends on how good of a job they do (and if the guy is balking, that's not a good sign) and what kind of shape it's in when you bring it in.
I should add: the two places I used were in Phoenix (when I lived there). Papago Plating was quicker and cheaper but did a shitty job (discoloration, peeling after a few years) but Metro Plating in Mesa did an excellent job. I've used them to rechrome exhausts, but also to straighten and plate a rear fender from a 1964 Valiant.