Just picked up my WG MOP bracelet today, from the same store where an SA told me about the onyx WG...... Today another SA was helping me and she confirmed that onyx WG is not the 50th Anniversary piece, and that theres been a lot of disinformation (I really wanted to tell her that it was her colleague at that same store that misinformed me)
So, she said that first it can't be 50th Anniversary because its been done before (I'm assuming the pieces that were offered to employees only as mentioned before)
and, secondly that it was a collaboration with an artist and Dover Street Market.
As for the real 50th anniversary, they really don't know yet.... even which month its coming out, its very possible that it won't be until later next year, but they are expecting "many surprises" she did make a note on my profile that I'm after turquoise, in case it comes out but she really couldn't give me a hint.
Only thing left to do is keep checking in and asking.....