Off Topic: How to glue to the interior of a lined fiberglass top

1977 Sportsman SE B200 with a permanent fiberglass camper top. The interior of the fiberglass top is "lined" (finished smooth and glossy). I would like to glue wood cleats to the inside of the top and screw the front panels of the cabinets to them in order to strengthen the way the cabinets are attached to the vehicle. What preparation of the interior of this van top do I need to perform at the spot where I want to glue the cleat, and what kind of glue should I use? Thanks very much.