If you're buying the fenders new it's possible it'll come with one. If not it's just a bolt and two nuts that can thread into whatever size nutsert you are using. Drill a hole that is big enough to barely clear the nutsert, tap that in straight then with two wrenches tighten down the bolt while holding the nut. Easy peasy. I'm clueless with JKs but are you positive you'll need to have new nutserts installed? Are there not existing locations that the new fenders will use?