I think that's the Eriba Pan (Familia). They're not fiberglass except for the pop-top (although they do advertise it as a fiberglass camper). From what I know, the frame and skeleton are tubular steel and the skin aluminum. Then the floor and the furniture are wood, and the walls (at least on the older ones) are lined witha kind of vinyl material. They're pretty neat -- I looked at a Puck once, and a friend of mine used to own one also.
PS: Isn't it funny that they would think their own trailer is fiberglass when it's aluminum? I don't mean that maliciously, but just in a "huh" sort of way.