I'm sure they'd have the skills, but I don't know that the paint would be the right stuff to use. I take it the guitars are made of wood? I don't think automotive paint would be flexible enough for wood. Most paint finishes that are poor are let down by the preparation. If his problem really is the paint itself, he might be able to flat it with 800 then 1000 and 1200 grade wet-or-dry and then buff the paint to a good finish.