Replacing Outer Cowl Panels on 55-2 Chevy

[Dads Burb]

The fender attachment nut on my outer cowl panels are gone on both sides. The area where that nut is located is in pretty poor condition. Someone tried to modify the attachment point. I have both left & right side ones from a parts truck that are in really nice condition. Was planning on using them, but not sure if I should just use a portion, maybe just try to use the attaching nut or remove them completely and install them on my truck.
Was wondering if anyone has just replaced part of them, just the nut or is it better to buy a repo part and install it.
Any input is appreciated.