Gel coat goes over raw fiberglass, but to paint fiberglass a good urethane primer and topcoat/clear would work well
Here's boat I've painted for a guy
Guy was tight and didn't want to spend money on quality paint so this is cheap automotive acrylic enamel with hardener (metallic, was pita to paint) Of course it won't hold gloss well over the years and just doesn't last nearly as long.
Magnum s/s lines, strut bars, carbon fiber bezel, indiglow gauge, Sony Xplod, inverted c/f hood, SRD lower tie bar '93 GS SE '95 Cobra SVT #2722 '68 Charger R/T 440
http://www.cardomain.com/id/mitmaks
