No wood in the hull but what you are seeing is the glass mat, yes fix it as it can absorb water. Being below the water line an epoxy like marine tec can be used. If cosmetic gel coat can be used to fix.
1997 2400 SCR
5.7 Vortec / Bravo 2
At four inches, I would call those gouges.
I had blister all over the bottom of the hull when I bought my boat. Ground them all out to dry glass and filled them with West System epoxy and 404 filler to thicken it to peanut butter consistency. Then sanded and painted with epoxy sealer paint before bottom paint. After 7 months in the water, still can't tell where any of those repairs were...I'd guess you'll pay a minimum of four hours of labor to have those repaired.