TOPIC: restoring hull, 1965 Lone Star Mustang

Does anyone know whether Lone Star was using epoxy (rather than styrene) for their fiberglass hulls in 1965? I have my floor/foampack removed, and need to add a layer of biax to the hull interior for both watertight-ness and rigidity. Trying to choose between vinylester and epoxy. I am aware of the general compatibility rules around each, this question is to try to determine if the original material was indeed epoxy or not.

Does anyone know? I once read some Lone Star literature about their manufacturing process, but can't find it again, probably wouldn't mention that detail anyway. Perhaps someone worked on a similar task and knows?

D in Mpls