Is there a trim piece at the top or any other holders for the mirror? If not,then the mirror is probably glued on and the trim just attached with silicone. I would get a knife under it and try and remove it. If you don't like how it looks with out it, then paint it or replace it.
We updated all the trim and fixtures in our house about 3 yrs ago. The only thing that we didn't paint was the door knobs. Hings, light fixtures, Took down the ceiling fans and disassembled and painted the metal with Rattle Can Rustoleum. Took longer, but Saved a ton of money.