Can i paint over factory paint on fiberglass or does it need to be primed?

the best thing to do is scuff the original paint with 800 grit sand paper then mask it off with tape and paper prime it then wet sand with 800 or 1000 grit then paint it then repeat and clear coatCan i paint over factory paint on fiberglass or does it need to be primed?
absolutely, or it won't stick