Hood Hinge push on washers ??

Those who have early As have torsion rods for the hood hinges like what trunk lids have. When they want to change the hinge to delete the torsion rods they have threaded the stud, added 1/2 bolts where there wasn't a stud, and used ny-loc nuts that were shaved thin. Lots of options in hardware to consider. Me.. I would just go to the local hardware store and buy push nuts. If they seemed too thin I would stack them in pairs.
A push nut isn't designed to be reused. There isn't a way to remove them without distorting them. When they are placed on a plastic stud the best method of removal is cut them off with a cutting wheel in a dremal. Any other method wil likely bring the end of the stud off with it. I learned that the hard way.