If they have a proper, good batch of paint (as in same colour paint, then on top of that a correct batch matching exactly to the original/master sample) then it shouldn't be a problem. The way the spray gun is set-up will also have an influence, e.g. they would need to have correct film-build thickness etc as per manufacturers instructions. If your paint has a metallic/mica finish to it, this may be fairly hard to match, especially mica, cos its a 3-coat system done by automated robots which I doubt the dealer/panel beater will have set up to do. Should be OK, interested to know if it comes back close to original.