No your new 15" A/T's will not fit on a Rubicon wheel and from what I remember from my own XJ days...

97-06 TJ Rubicons use the same bolt pattern as your XJ 5x4.5" however the wheels are 16" I am assuming you are asking about these wheels because the 07 and up JK Rubicons run a 17" wheel and the bolt pattern is 5x5". You can find adaptors/spacers that go from 5x4.5" to 5x5" but then your lookin at larger tires and I would assume some clearance issues if you are running stock suspension height, especially if you have sagging rear leaf springs like most 98 XJ's out there. But it is a good excuse for a lift

245/75/16 with a 2" Lift

 

Yeah what he said ^^^. The wheels will bolt up if they are from a 03-06 Rubi...but the 15" tires won't work on a 16" wheel.