We drill/weld Dodge/Ram truck frames even after they went to the hydro formed frame rails in '03 per Dodge Body Builders guide instructions and TSB 13-001-03 dated 2-7-03.
My current '03 Dodge trucks frame mounted hitch brackets were welded into the main frame rails when I bought the truck new per my request. No issues. In fact many upfitters recommend their products to be attached with a solid weld instead of a bolt and nut or frame clamps.
I would use all 4 anchor brackets mounted to the trucks main frame. Then use the spacers if required when attaching the bed rails.
