Panel Preperation

Can you paint on top of the black finish that is on new panels? Or should it be scrapped of and the primed and painted?

As far as I remember you want to use a scotch pad to scuff the panel a bit then prime, then sand, then paint etc etc

If its the type that goes soft with celly thinners you should try to remove it, or at least get through most of it so the paint adheres to the steel and not the black stuff, if you dont you will find the new paint will chip or flake off easily. If it doesn’t go soft then just flat the surface of the primer.