...To anyone who is searching this thread looking for information about replacing their radiator.
Turns out, the radiator that came out of my jeep was not that of a 1999 wrangler, but a 86'-87'. From everything that I researched I found that a new Murray radiator for a 99' wrangler was what I needed. Ordered it online, picked it up, and it was too big. I took the old radiator back to O'Reilly's and they were able to match it up with a 86'-87' radiator. I bought this jeep used so how or why it was this way is still a mystery to me, but for whatever reason the correct year radiator did not fit. I just thought I'd share this information in the event it might apply to someone else too.