I think he means that if you trim the fender on a 96 and earlier like the 97+ from the factory, can you put a 97+ bumper on said trimmed 96 and earlier, special consideration going to the wrap around end-caps.
To answer you question, i dont see why not. I dont know how the short endcaps from the 96 and earlier xj's mount, my guess is it would be drilling a few simple holes to mount the endcaps to your pre-96 cherokee.