Marcel
Remi is correct. The W.34 was too heavy to be registered in the D-Ixxx range and should normally fall under the D-Oxxx range. However there is only one problem with changing the registration you want to D-ORUV and that is that this is stated to have been A BFW M.18b .....
Germany did occasionally use the same registration twice, so nothing is impossible. Do you look at a photo or do you have something else we can use??
Cheers
Stig