They will need a couple of things to program the cluster up.
VIN and Kms are the obvious things, but they will also need,
Engine type (L98, L77, L78, LS2, LS3, SIDI, 3L, 3.6L, etc)
Transmission Type (4, 5, 6 Speed Auto, or Manual)
Chassis type (Sedan, Wagon, Ute, Long Wheel Base model)
ABS / ESC...