Welcome to Stovebolt
Decades ago there were repair eyebrows being made, they were made oversized to slip over the existing metal and be welded/riveted in place...not a good fit at all and took lots of bondo to smooth things out.
If your eyebrows are rusted out then more than likely your fender heal and rear brace need repair as well. With the high cost of bodywork labor it's almost cheaper to buy the new fender rather then repair a rusty one.
Mike B
