It depends on where you take it. Some places (Maaco) will just paint over the surface. Others will light sand, and then paint. Full restoration places may take it all the way down to bare metal before painting.
Your best bet is just to have the car lightly sanded. Don't go down to bare metal, you'll take of the Electrocoat that is under the paint which prevents corrosion. As soon as you hit bare metal, say hello to rust.
Look for a shop that will sand the base coat (black) all the off. A decent sander can get rid of all of the black paint without coming close to hitting bare metal.
