Yes but that is to be expected from known processes already.
An orbital can have two objects in it with opposite spins, when they have the same spin they would occupy the same space and thus couldnt exist in the same orbital. Therefore an electron with the same spin as another must occupy a higher orbital than one with different spin, thus must have more energy. More energy means more gravity.
So in short one would expect flipping spin would change the gravitational field strength.