I will leave the fiberglass to the experts in that field.
The snaps by the beds are for a wall pad/cushion. They keep you from rolling over in to cold aluminum during the cooler camping trips.
The pad is not much bigger then the area in which you see the snaps. I will see if I can dig up some photos for you. The ones I have seen ususaly match the couch fabric, but you can make them out of what you want.