Did you put on a "sealer" coat of epoxy to the hull interior and let it cure prior to applying the fiberglass? If so (and if it were my boat), no "requirement" to fill the weave. I personally would do it anyway just to lessen some of the valleys because dirt gets trapped in there pretty easy and can be a pain to wash out.

If you applied the fiberglass directly to the uncoated wood, then consider one weave fill coat. If you got any outgassing from the plywood, you might have pockets of gas trapped in the cured epoxy that will easily got popped. Perform a light sanding and apply one more light coat. You won't use nearly as much epoxy as you did to wet out the fiberglass.