There are buggered screw heads and there are buggered screw heads. A lot of them can be repaired by putting a slot width metal shim in the screw slot and pein the metal back to the shim with a punch and small hammer, then clean it up, and recut the engraving, if any. If one is too damaged for simple repair, you have to make some decisions. First, are you able to cut the thread to make a new one, is it important to the possible sale of the gun to have all original parts( even if some are repaired, do you know someone that can do that level of welding), and are you able to clean up the welded screw head. I suspect that this " soul searching", would result in more new screws being made than old screws being welded up.