It's been a while, but I had to reinstall the front bumper on my 1993 F150 a few years ago and as I recall it's 4 smallish bolts into what basically amounted to some sheetmetal clips.
Well I searched around and decided to purchase a plain painted bumper from jeff's bronco graveyard. They also had the bolts and brackets. It looks like the people who owned my bronco before me and attached the ranch hand bumper broke the factory brackets off and just welded the bumper to the where the brackets were attached. All in all, it was just difficult for me to see how a stock bumper was supposed to be attached.