Yes, the Jeep code for your Cherokee is XJ.
A 1995 XJ 4.0 actually comes with a petrol tank protector (or 'skid').
As your's is a sport, it must be a 2.5 petrol, so may not have one as they are lower spec and have bits missing.
So skids are available, and you don't have one, maybe you could get one of a scrapper 4.0. If course it might not fit with the LPG tank there.
I personally wouldn't worry that much, as 1) A tank skid isn't going to help if you're being rear ended by anything heavier than a Reliant Robin, and 2) LPG tanks are very strong indeed.