No. They are talking of offering some reciprocal benefits for elites from the partner program, when flying on the other airline, but nothing concrete has been announced yet.
And presumably it will be like every other partnership, where you get some of the benefits of the partner elite status (Mosaic in this case), but you retain only your AA elite status. Just like AA Platinums don't become BA Silver, they just get some of the benefits BA Silvers enjoy.