The moon's radius is considerably higher than the "potato radius" of some 200-300km depending on material (https://arxiv.org/ftp/arxiv/papers/1004/1004.1091.pdf), so even if you take the two halves, and flipped each so their domed sides faced each other, the moon would just flow together and re-form as a sphere.

If you merely slice it and push the two halves apart by a fraction of an inch, they'll just snap back together again.