As 52Carl said, the bracket originally had the heavy felt type tar paper wedged between the bracket and hood underside. Most has been gone so many years present owners don't even know it was ever there. You can wedge some back in, unsatisfactory, or you can use windshield urethane for a secure bond. Some places it will be 1/4" or more thick so for a neat job having the hood upside down will help. For a near forever fix you can use 3M Panel Bond.
