Sorry I didn't respond earlier.............I have an '03 and if yours is the same, you're absolutely correct. Pop that little "gear-shift pattern thingy" off of there and the nut you are seeking will be revealed. I put some pretty good gouges is my stock knob trying to remove it to put on my Rock Knob. Felt really stupid when I popped that little cap off. Hope my post is not too late to keep you feeling as stupid as I!
BTW, the Rock Knobs are really cool..........every one unique. So, I now have a one-of-a-kind Jeep!!!!! (...........mmmmmmmm, I guess they all are).
Good luck and keep us posted.
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The only terrorists I fear reside in Washington, DC.
'03 TJ - 31x10 Trailcutter M/T's, 9000# Winch, Hi-Lift Jack, TopFive roof rack, only vehicle I own, takes me everywhere