This isn't a 4.7L engine he is asking about, it is a 4.0L. The oft stated claim that only oem are acceptable in any Jeep engine is a load of bull. I have run ngk copper plugs in both 4.0L and 4.7L Jeep engines for hundreds of thousands of miles without a single issue. Have also run non oem plugs in a 4.7L HO engine, though they weren't copper. Even running 16 NGK copper plugs in a 5.7L hemi right now with zero issues.
Mopar doesn't make spark plugs and there is no reason to purchase plugs at a stealership. Go to the local auto parts place and get a set of ngk or champion copper plugs, install them in the 4.0L and never look back!
Chances are you will get the exact same plug you would have purchased from mopar for less money.