Bryce, I don't know whether the brooch recently worn by QEII which belonged to her mother, QEQM, came from Queen Mary or not - so I have no idea if it was one of Queen Mary's wedding presents.
On the other hand, I don't think anyone has yet seen a photo showing Queen Mary wearing the brooch.
The trend on the earlier discussion on the board was to suggest that the clover brooch, now worn by Princess Michael of Kent, was the gift of the Milners - but obviously none of us knows for sure. We can only say that that particular brooch was worn by Queen Mary as a young woman.