I have found a Neumann stand mount in original packing. It is marked SG 367 product Code 006143. It is supposedly a silver stand mount for the U87.
I have tried it on both a U87 (the threads do not mate) and a U87ai (which has the same sized threads) but the barrel of the stand mount doesn't seem to be long enough to connect to the thread on the U87ai housing. It will fit when I remove the base of the U87ai but otherwise no chance.
Does anybody know which stand mount I actually have here?