That age would have a metal Sportsmobile script in the door, kind of like old car models. The picture is unfortunately too blurry to make out what that is. It's lovely though, good find!
It could say Econoline, too. The older vans didn't have much for emblems or lettering telling you what they were. Our 1965 Chevy van had a Chevy emblem on the front and a small emblem behind one of the front doors that said Chevrolet.