I'm not familiar with the Hercules brand of bumper, but years ago when I was in the auto parts biz, we sold a few brands of aftermarket bumpers which HAD TO BE used with the proper mounting brackets.
The mounting brackets were specific to the year, make and model of truck that the bumper was to be bolted to. Therefore, we didn't have different part numbers for a Ford bumper versus a Chevy bumper because all the bumpers were the same -- it was just the mounting brackets that were different.
Maybe that bumper is the same?
Or as you suggested, it could be off a different make, or different year, of truck.
Good luck, and enjoy your welding project
