I have the police commemorative derby cover and think it would look cool if I had the area around the badge and inside of the ring done in gloss black, but can that be done without damaging the badge and outside trim ring?

 

Not sure about the damage, they can mask off any area that you don't want to be powder coated, however, the curing process for powder coatings reaches 450 degrees or higher. If you think the badge and trim will withstand the heat then go for it. Also be aware, that they sandblast or beadblast prior to coating in order to prep the surface for proper adhesion. That usually means masking the piece twice.