Previous owner of mine welded on the brackets from a 78? Chevy truck. You could probably drill and bolt on the brackets instead, and maybe move them in a little further than what I have.
When I put the new bed on, I cut off the wrap-around ends of the bumper, because the bed that was on the truck when I got it had to be dented to make room for the wrap-around style, and of course I wasn't going to dent my new bed to make the bumper fit.