Attaching Angle Strips on a Stepside 64 C-10

[Green77bus]

Ok so it is a week until Christmas and we are finally ready to rip into our bed of our truck. You will see in the pictures below that someone before us has welded in some angle iron instead of the angle strips that belong there. I am wondering how everyone else has gone about replacing and attaching the angle strips to the side panels of the truck bed. Any advise or information would be greatly appreciated.