I'm trying to remember how this went and I couldn't find any info on the net. Back around 90 a buddy had a 79 Chevy and "I think" it had a bumper from the newer body style on it. If I remember correctly it was a front bumper turned upside down and run on the rear of his truck. Supposedly bolted up. I remember it had the wide plastic trim on it and looked good. We had a friend that worked at a dealer and could "get" new slightly damaged stuff they swapped out on new trucks.
Please keep in mind that my brain is middle aged and I could be completely wrong!!!!!
But if anybody has an 88-98(?) front bumper give it a try on a 73-87 rear. I'm pretty sure you had to run it upside down though. And once again I could be imagining this, but if I'm not ........ cool. Maybe I've contributed something useful that's been forgotten.
Added... I'm going to try to get ahold of him to find out any details.... it's bugging me. Mind you this was a 2 minute conversation over 20 years ago, and alcohol was involved.