i would prob solder them up and grind it down. i wouldn't weld because the metal is already going to be a bit thin and you may make the pin holes bigger.
actually welding is the best way to fix it, your replaceing metal with metal. All you have to do is put a piece of different type of metal ie. brass or aluminum, behind the hole and hit it with the welder, grind it and you have a solid metel piece again.