I know what all of those "J's" are except the KJ and the WJ. What styles are those? They are what I thought (there I go again, thinking LOL) it might be.
XJ's are the Cherokee in their current form. I believe that started in 84. If yours is a '79, its got a different body style and its not an XJ. I can't remember what the "J" term is right now. You might be able to find it at ifsja.org, a website devoted to the full size Jeeps like yours. There will probably be alot more useful things than the model name for you there as well. Let us know what you figure out.