If it still has german papers, it should work well at the “Graukittel”. Is the sticker on the seat cowl coated with paint? Maybe you can get the correct repro one for 85 model. The one on the pics is from 84 (and 85/86 US).
The German registration documents are still available;
the motorcycle is a first-hand purchase, the original
owner died of a heart attack and I bought it from his widow.