If you have the hatches as a starting point, you can grind off the chips and cracks and fill with thickened epoxy, fair, sand the whole thing and paint. You may need to add some glass to reinforce some structure. You may have never done that before but you have a 24 year old boat...time to learn...otherwise you are going to pay alot.
Given that its an old boat, you don't need to perfectly match gelcoat and non-skid pattern. Plus, you are probably putting cushions on them so you only see the edges
Because they are separate pieces, you don't have to blend your repair into undamaged areas. Its a good project for learning fiberglass work. Do some research, practice on something small.
Will your work be as good as a Pro? NO, but it will do for a 1999 hull.
Heres an example. This is thickened with High Density filler. It will be sanded then get Low density "fairing" filler and be sanded smooth .
FYI, epoxy doesn't stick to packing tape so use that to your advantage...