Yes, after hammering out the dents and massaging them into shape, buffing and polishing can yield good to excellent results.
I did this on a 1976 F100 grill made from aluminum. It was a pain in the neck getting the thing into position to work the dents due to it's large size but once I did it was relatively easy to shape.
Once straightened, I buffed out the waves and then polished the whole thing with a wheel chucked into a drill.
There was a tear in the metal that I was able to flatten out and massage the edges of the tear so that they met. Once they were even, polishing made the slit nearly invisible.
I'm not a bodywork guy and have never done it on painted metal but the pliable aluminum was fairly easy to work with.
Here's a company in Texas that does a good job restoring hubcaps and trim.
http://www.trimpolish.com/index.htmlHubcaps.com sells hubcaps and restores them, too. I've noticed that their used hubcap prices have gone up considerably since I first purchased this company. Of course that was 10 years ago but I think they've become more aware of the value of some of these caps. Their old caps were typically around $15-$30 each ('64 Galaxie, for example). Now they all seem to be pushing $100 or more.
http://www.hubcaps.org/cars/