Around here they're worth whatever someone will pay for them. They were very common options back in the day also on Fords, Chevys and Dodges. I've had them on a 72 Chev, 74 Blazer, 72 and 73 J-4000. Other than mainly the model specific frame mounts, they're all pretty much the same bumper and not rare. If it's a "FSJ"specific bumper, around here it might be worth a couple hundred? What lessens the value some will be wrong mounts, rusted out or missing deck plates. They're all going to need clean up and painting so that's moot. Unless you sell/buy local, shipping is likely going to be a deal breaker. I'd guess you're in the $100-$200 range depending on fit and condition and local demand. Just my opinion from my part of the country.
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