Nope sorry- in fact you might as well get rid of it as it simply has no use on your 84. It will ONLY fit the 79 model which I happen to have. I'll volunteer to take it off your hands so you don't have to worry about paying the disposal fee!
As others said, it'll work fine. It will also work on the YJ's if you modify the rear gate.
CJ7, 258, Dana 20 T-case, Dana 30 & AMC 20, TFI Ignition upgrade, MC 2150 carb, YJ tub mod