I have one of these lying around somewhere. Kept it as I planned to find a nice white Beomaster for it (the 1200 that came with it was broken and sold on).
However, I just bought a nice & complete white 70s Beosystem 2000 and that one will be wall-mounted instead.
Guess this is pretty rare. Bracket is complete and works flawless (not bent or something like that). Some very, very small scratches in the black glossy finish on top.
Pictures can be found in this thread.
Price is 40€. That's what I paid - was the only time I ever saw one, so I guess it is worth it….