I would say the ground glass holder is from another camera (a Voigtlander). The metalwork of the lens mount and the knobs on your camera are not Voigtlander. The Avus, Vag, and Bergheil cameras (most all types of these, and there are many - check Claus Prochnow's books (in German, but with pix of all models ad prototypes) ) typically have the Voigtlander name or logo on the drop bed of the camera (under the geared tracks that move out). I really doubt yours has the Voigtlander logo on the camera itself (non exchangeable parts), but if it does, I'd be very interested in seeing more detailed pictures

Cheers

Tim