The hitch is standard on the V8 and option on the V6 for 2006. V8s have a weight distributing hitch (tube hitch--visible under the bumper) and V6s have a weight carrying hitch (no tube, just the receiver opening). You will get a ball mount and pin, but no ball.
If your truck doesn't come with hitch, don't worry about it. You can get a Hidden Hitch for about $150 and it's easy to install. I didn't order the hitch when I ordered my truck, but the truck did come the 7-pin wiring harness and brake controller harness.