You may want to stop by a car restoration shop or two and see who they use, or if they can send it out for you.
When I was restoring my GTO years ago I sent some chrome pieces out through Don's East Coast Restoration on Akron St. Lindenhurst. They came out incredible, and the turnaround time was really good.
I had another guy send out a bumper once, and although the work was excellent, it was gone for far too long, so I would never recommend him.