If you have the fenders removed, you can see the plate the hinge blots actually thread into. It captured by a second set of tabs. You can cut the tabs, and remove the plate, then drill out the bolt remnants and tap the holes. Then just slide the plate back in place, adn weld the tabs back. That plate is absically a giant washer, so the tabs holding it to the body are not under any stress, or visible later.
