rbier wrote: maybe it was build in May-June 1969 as model year 1970.
That's possible, Ralf, although the Ducati production year is usually considered to run from September to September (Why September? Because that was when the factory came back to work after the summer holiday).
Btw, having said I'd never seen a picture of a Scrambler with a rubber rear light mount, here is one ...

I'm inclined to think this is a photo/drawing from the period, rather than a restoration. My only doubt would be that the seat doesn't have a passenger strap which it should. The caption says it's a 1973 bike (which seems right), and the bike would be a 450.