That's not that great of a deal for a 4x2 since I've seen 4x4's go for about a grand more--especially since we're getting towards the end of the model year and they're going to stop making the 15's soon, if not already.
And I'd seriously consider getting a 4x4 over the 4x2. The full time 4WD in the Limited is part of the reason to get that truck.