TOPIC: Fiberglass

I'm restoring what appears to be a 1959 or 60 wizard Marlin outboard boat. The fiberglass inside the Boat is in good shape can I lay just a resin hardener over that and smooth it out or do I need to rip the fiberglass out and replace it also. I also have holes in the side of the boat where they had put the snaps for a cover can I use like the fiber bondo to fill those holes.