That looks very much like the Mobile glide I saw at Colin Hydes Trailer Restorations. He's redoing one and has been talking about it on The VAP.
Google Vintage Airstream Podcast or go to www.thevap.com
As I remember there was an identifier ( plate maybe) on the tongue?
Colin is here on the forums as Colin H , private message him, I'm sure he'd be interested in hearing about another one of these!