The car has been sold in 1976. I found the announcement in an old car magazine.
What I found out is, that the seller came from Burgwedel near Hannover and the second number is today used by a bus company called Kelpe.
All the technical data are named - unfortunately the name of the car can not be read clearly.
The left letters look more like "ARRIATHA" and the right rear letters like "AFFIENAR"...