It could also have something to do with the switch from the leaf springs to the coils in the rear, in which case the 90-93 bars might fit 89 models that came with coils (V6)since both setups (4cyl leafs,6cyl coils) were offered in the 89 models that could lead to confusion...I'll see if I can compare my 89 tomy 91...Wont be able to be very accurrate w/o removing the bar but should be able to tell if there's a couple inches difference.

99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..