Answer:
Caution: The air control bezel uses a thin plastic overlay fixed onto an open frame. The radio bezel has locking ribs on the bottom- when removing the radio bezel, the ribs can puncture the air control bezel. Place a piece of heavy tape or carboard over the air control bezel to protect it.
Use a thin plastic tool to pry the bottom of the radio bezel until it comes loose. Then work around the sides until the bezel separates from the dashboard. Unplug the connectors at the top. It will be attached by the AC harness- remove the connector (which can be a bit tough) or just flip the bezel over the steering wheel.
Remove the three 10 mm bolts that hold the radio.
Remove the radio and unplug the connectors from the back.
GM radios are a double DIN style, so most replacements will need an install kit that will add a blank plate or storage pocket.