Most likely. Gm stopped allowing us to buy radio service manuals after the '94 models so they could lock up the repair business for their two grossly over-priced repair centers. In response to the many people buying high-quality aftermarket radios at less than half the cost of getting an original one repaired, they cleverly started building the Body Computers into their radios. The results of removing the radio varies by year and model. Some won't start. Some are just missing some functions like the chimes. Some will start and run normally and all functions will work. If you don't know what will happen with your car, I'd recommend disconnecting the battery or radio in the dealer's parking lot to avoid the possibility of needing a tow truck.
For those where the original radio must remain in the car, the aftermarket industry offers a "radio relocation kit" that lets you mount the radio in the trunk, and just cut the speaker wires and run them to the new radio. Be aware that some computers on some car models will lock up if you disconnect the battery or let it run dead. Just another trick designed in to get your money after the sale.