I replaced my cluster last fall. Here's what I did;
Went down to local Stealership and had the service technician look and record my mileage. He printed up a copy and handed it to the Parts department so they could order me a new(reman) cluster with my exact mileage. Cost for my 2008 was $295 plus $550core charge(yeah, I know right...) Anyways, I did NOT have to leave my truck there. Service Tech said "I'm not worried about the 2or300miles you could put on in 3-4business days(even though it was only 7miles..haha)
When the new one came in, I had already tore down my console in my driveway(knee cover, radio bezel, cluster bezel) so I took the starbit style screwdriver with me to the dealership to take out the couple of screws that hold the cluster in place. I walked in the parts dept and paid the $295+tax along with the $550 core charge and took the new one out and installed it(less than 10min) Once I knew the new one was going to program itself correctly, I refunded my old one for the core charge. I was afraid to hand mine in before making sure the new one was going to work. (btw, when they refunded my the $550 for the core they never refunded the sales tax, so I had to go all the way back after I got home..just an FYI to look out for)
The dealer needs your mileage and your vin#, nothing else. As a matter of fact, there was a website name on the cluster but I didn't write it down and I'm not tearing apart my truck to find it either but I did see a site online that does reman.'d clusters. I bet all you need is proof of mileage(which is asking tech dept to print you out the proof or a garage to print it out)
Buying used clusters off Ebay is not recomended as they are pre-set to auto program. Once they program to one truck, they keep all that info(supposedly from what I have been told) The dealer provides your vin# which shows the options so that the options in your truck can be unlocked/accessed. Kinda like the foglights that need dealer's to enable the circuitry in 2006+ models. It's all in the cluster.