Many thanks for the suggestions.
I finally got the chance to take a close look at my friend's Nigel Dennis kayak. There is no bolt that goes right through the fiberglass. The ripped out deck hardware was actually held by bolting into a brass plug. The brass plug was ripped right out of its fiberglass "cup". What resin or epoxy was used by the manufacturer to hold it there I don't know. We're about to start some reshaping of the road/rock rash using 2-part marine putty. We sent an email off to Wales asking how they affixed the brass plug so we can do the same thing.
So thanks again, appreciated.