Patrick,
The basic hull for all Nimitz-class ships, as far as modeling goes, would be the same. The changes are in the number and location of the sponsons, and the various hull cuts beneath the flight deck. The Nimitz class ships are having their bridle arrestors removed and no CVN since the T. Roosevelt CVN 71 has been built with any. (These are the extensions at the bow and angled deck at the ends of the catapults. They were once used to catch bridles that connected aircraft to the cats. No currrent Navy a/c uses them, so they have been removed.) The other major noticable difference is the configuration of the mast aft of the island. The newer ships have "solid " sides, the older ships showed the framework. As the ships are being refueled and overhauled the masts become "solid." Each island will have slightly different details too.
The Reagan has no after mast and a much different island structure. The flight deck only contains 3 arrestor cables, the other ships have 4.
The CHINFO link above is a very good place for CVN photos.
Mike