bheston...U are correct, the vin along with other required data will have to be relearned into the replacement radio using a hand held scanner. The Tech II is what is used and I'm not sure if any aftermarket units will work.
In addition U are also correct by saying many if not most of the late model GM radios are not interchangeable between models. Your model year was among the first phase of radios using the class II serial data stream for operation, so U should be fine swapping similar units IMO