Based on the size and the tell tail hatch in the back, that is a teardrop trailer. The originals showed up as GIs returned from the WWII. There was surplus aluminum galore and a surge of people getting back to nature.
I venture a guess that inside the cabin area is a wall to wall matress and the rear hatch is a kitchenette? I did a bunch of research on teardrops years ago and was planning on building one but our family grew and now it is a back burner dream. With gas prices going up they are only going to get more and more popular.
Click yourself over to http://www.teardrops.net
and contact them. They will either know it or post it on their mystery teardrom page. Let us know what you find. As far as I know there were very few fiberglass teardrops around back then, none commercially and only a couple new ones today.