Well when you mentioned Monokote as an option, I figured they might be covered in monokote already

"Glass and Paint" is a two step process, you cover them with fiberglass cloth and resin,, then paint.

Since now it seems they already have silver paint over fiberglass or silver gel coat, all you have to so is paint,,
I would wash with warm water/soap to remove any grease or mold release agents, then lightly sand (420 grit) to scuff up a little the area you'll be painting,,
I'd also do a "test" area to make sure the paint you used isn't going to eat the paint that is already on the floats

good luck