if it is fiberglass, then no, because the fiberglass has been molded with anti-slip texture in it. if you paint over this you will no longer have the anti-slip feature.
You can use Interdeck or another non-skid paint over the anti-slip portions of the deck.
I just painted my deck. I did this because the previous owner's paint job was starting to crack and peel around the hardware (he didn't remove hardware before painting, so moisture could get underneath), and because I did a bunch of fiberglass work around the windows and that needed to be painted.
To do the job properly, you need to remove all the deck hardware, and then paint. It's a chance to rebed all the hardware properly if you haven't done that recently, so that's a plus. It makes the job take a lot longer and requires multiple people though. If you don't remove all the hardware, so the paint edge is underneath sealant, moisture will get in there and wreck your paint job within 1-2 years.
If it hasn't been painted before, there's probably mold release wax still all over the deck, so you'll have to sand everything and then use some solvent to get rid of residual wax.
If it has been painted before, I think you just need to sand down the old paint job. At least I hope that's all, otherwise I'll be crying this spring, since that's what I did for prep...
You do the nonskid portions by painting the glossy first, having a healthy overlap onto the areas where the nonskid will go, giving it a week or so to cure, then taping over the glossy areas at the edge and painting the
You'll need to know how to roll'n'tip. I got good results, but not as good as a sprayer. My problem was tiny little bubbles. Might be dust in the air causing them, not sure. They aren't really noticeable, and will probably disappear as the boat gets used (same as the way they're all gone off my polyurethaned wood floors in my house after a few years).
My 30' catamaran took around 16 hours to remove all hardware, 16 hours to paint the 'glossy' areas, and 16 hours to paint the nonskid, and another 16 to put all the hardware back. So that's a huge time investment as you can see. This was with multiple people removing & putting hardware back, and only 2 coats of the glossy and 2 coats of the nonskid. I would have preferred 3 coats of each but I ran out of time, I was losing my boat shed after Labor Day. I'll be doing some more painting in the spring, just minor bits & pieces though where the paint seems bit thinner than I'd like.
That's another expense, you'll want the boat somewhere inside to do this work. Otherwise you'll get whatever the wind blows at you, stuck on your boat.
That's the long answer to painting your deck. The short answer is "no", don't do it, if your deck isn't already painted. It's a pile of work and will need to be redone in 5 years or so.
I used Interlux Brightsides and Interdeck. No need to prime which is nice. I didn't use a 2-part because I don't feel like dealing with fumes, and the 1-parts are more "repairable". Just sand down and feather new paint over the damaged area.
It looks really nice now overall, much better than it was before. Biggest problem I have now is that all the old crusty hardware looks terrible when reattached to the shiny new paint job... so I've bought new cleats and I'm talking to a re-chroming company to clean up some of the winches, locker hinges & stanchion bases.