Rusty rear liftgate hinge bolts broke

[VOS TJ]

Rusty rear liftgate hinge bolts broke where they meet the fiberglass attachment point in the top.Had to be drilled out.Looks like a fabrication job to install the new hinges since the bolt threads are destroyed.Anyone experience this ?Any thoughts.
Advice?Thanks

 

[Plumber1]

 

[VOS TJ]

Hope this helps clarify the issue I've got with stripped bolt holes where the liftgate hinge attaches to the top.