I think you are correct about your backspace.Yea you're right. Hmmm Maybe my back space is not what I thought. I didn't order them. Dealer had them on there when on the lot. They show online as 5.2" but maybe they can be ordered with other backspace as well.
What I was trying to convey is there is even more room on a Rubicon because of the wider axles. I have a JK w/ Dynatrac HD60 and I'm able to run 5.5" backspace on an 8.5" rim with 13.5" wide tires and keep the turning radius basically stock. It also improves my scrub radius over other rigs that are having to run 3.5" backspace.
The new axles on the Rubicon JL simulate what Dynatrac did with the HD 60 axle. At SEMA AEV introduced new wheels with increased backspace to (I believe) 5.8 because of the new JL design.
I prefer as much offset/backspace as I can get without bind and rubbing. Better for turning, steering (running straight/scrub radius), bearing stress/wear. Handles and feels more like stock Jeep.