If the factory paint is not peeling, they can scuff sand it and paint over it.
I stripped the modling, glass, seals, and interior out of my RC and got a few estimates from different shops. I got a quote of $7,500 from a shop known for doing high quality muscle cars & rods. I got a quote of $5,200 from a recommended shop in town, but that I'd never heard of.
In the end, I have a friend that owns a paint shop, but was in the middle of building a new shop & paint booth, so had to wait a few months for him to do it. His bid was $4,000 and I had the comfort of knowing him for a long time (we went to high school together).
All three prices included doing a color change. The original was green, but I went with a newer green, and changed the top to khaki. He also painted the metal parts of the interior, the metal dash skin, door jambs, underhood & tailgate.
With a color change, you will need to do the door jambs, interior metal parts and underhood to make it look right. It will probably cost $4,000 to $5,500 depending on the shop and amount of work you are willing to do. If you strip everything they would have to before getting started, you can save $1,000 to $1,500 and don't have to worry about the shop loosing your trim.
BTW, my paint job turned out really well. I'm very happy with it. The truck is not totally back together yet, but here is a shot from when I picked it up at the paint shop.