Just make sure they hand polish your pistol, buffing with wheels on a pistol more often than not rounds sharp edges and makes the gun look terrable.
Check to see how they polish first. Bluing is easy, it's the polishing that makes the job.
If they don't hand polish a pistol, check with S&S Sporting, they do. The gunsmith, Scott Null restores a lot of very expensive weapons and does not touch a polishing wheel to any pistol and not many rifles. It's done by hand and his prices are reasonable. 208-313-1570. Scott is one of the few true Master Gunsmiths left.