Oh rot it is!!
I've done most of my deck, the antiskid was almost(mostly gone).
I sounded ( with plastic hammer) the whole top and used a forstner bit to core out vague areas checking for dry areas( few) most of the deck was cut out from the top, I didn't care about replacing the topskin
although this is smart if you like what you have(Don Casey's- Hull & deck repair).
I'm going to use a plastic grid (coated with mold release wax) and some quick setting epoxy, should make a nice antiskid grid.
I cut out and replaced 1/2 the cockpit sole with, I think 1/2" marine plywood and more epoxy.Work,work, work,etc.