Maybe in the US they weren't put in a lot of rigs, but I'm from Canada and worked for Golden Ears motor (Jeep dealer) and there were quite a few. No torch marks on the axles (YJs are spring under, and Cherokee are spring over plus shocks are in the right place) Same with Comanche, which might be a bolt in (It's SUA also, but I never tried bolting one in)
I'm currently doing a SOA rear on my Comanche with a Model 20 ('86 only Metric tonne models came with them stock) I picked up from a scrapyard. They came with 1 piece axles like '80 up full size Jeeps (IE: Grand Wagoneer and Jtrucks) but have the same bolt pattern as XJs. (Brake drums were REALLY hard to find as they were 11". I had to redrill some IH ones that had the right offset)