In 2007 there was a major redesign and thats called a JK Wrangler. 06 and down to 97 is a TJ Wrangler. They are quite a bit different. If you looking used then look at both models.
In 04-06 there is a TJ Unlimited called an LJ. What I have is an 05 Unlimited Rubicon. The Rubicon is an available package that adds locking axles in addition to other things. That is 04 and up, even through the design change and into the current JK platform.