I think it really depends on the dealership. My friend owns a body shop and they do work for the CHP, Insurance agencies, and a lot of car dealerships in the area, as well as costum/show work.
Also, body shops can color match your paint. Your paint code is on the sticker that is on the inside of the driver side. They could match it up that way, or for an even better match, they'll take a computer and color match to your car, then refine it from there until it is perfect. That way if your paint faded just a bit over time, it'll be an exact match. No matter how exclusive the paint is.