dont quote me on this, but i heard from the painters at the body shop i worked at and i have no factual evidence of this.
i think its a chemically different paint then when you get body repairs. i believe its baked on to fuse it to the plastic (or metal) so it lasts longer and wont chip or crack as bad when you get little dings or fender benders.
and davis is right... i doesnt matter. as long as you find a good shop that does a PROPER prep job, separate paint room, drying room and has a clean well ventilated facility... you should end up with a nice paint job.
-pete