I enlarged the pic and it definately says Airstrea is all I could make out, I would suggest that it may be a late 50's edition of the international travel that AS made for overseas trips.
I was on the blue ridge parkway and run upon a book about alum trailers and it had one of these in it. I believe if I remember correct it was the predicessor to the Avion.
As far as floor plans it was not uncommon for manufacturers back then to flip or switch them around slightly to sell an ordered unit.
I believe that if you do some further investigation into the serial number by running a history through DMV you may find out more information.