Pre 97 bumper to repair a 99?

I have a friend in the state below me that just had his '99 XJ rear ended.
He knows I just removed the stock bumper off my '93.
If we can repair his rig with my old bumper I will be driving south after work.
Can anyone tell me if the metal part of the 93 bumper will replace the center part of a 99? I'm trying to save myself a trip if it won't help. I'm wondering if the endcaps are the only difference.
Thank you in advance for your advice.

I think you'll find that the actual cross-section of the bumper is different, so the brackets must also be changed, and it won't mesh well with the end caps. I don't have my two jeeps on hand to compare width, etc. to see if you could still do it with a little bodging, but I don't think it would ever be a neat job.