I have what's left of the bumper fillers off of my '74 Challenger. The parts aren't great but I'd hate to just toss them if someone can use them. I don't think anyone reproduces these parts. I had planned to repair them using 2-part urethane flexible filler. Anyway, take a look at them and see if any of the parts may be better than what you have.
How does $50 plus freight sound for the whole thing? Of make me an offer if you don't want it all.