Just wanted to report back that I contacted Gorilla and they put me in touch with thier Chemist who was extremly helpfull.
She indicated that Gorilla Glue begins to lose adhesion at about 215F and when she realized that the magnesium can withstand up to 1,200F she said I could simply burn the glue off as its an organic material.
So, I'm going to bake my magnesium piece at 250F - 300F and remove the broken piece, then torch the Gorilla Glue off. Ultimately, I am going to weld the piece back on as I need it to be exactly the same... heat resistant over 550F, conduct electricity, etc...