Running a 2.5 inch rough country lift. If I remember correctly they came with Endlinks.So, normally the top bolt is part of the end link (on stock end links at least) and not a thru bolt... That swaybar end link looks funky (to me) unless they've changed them for later/different models... if so, then just ignore my post.
My stock sway bar links looked like these: https://www.quadratec.com/p/mopar/f...UVtyxU1hlDnGasARHaaiVom8cn3z9Wq0aAio8EALw_wcB
Those are long gone now, otherwise I'd be able to confirm for ya.
If you're still looking to replace the nut only, then maybe the guys are @AllMoparParts.com can help you find the part. They're pretty darn good at tracking things down.