The Z/28 didn't include the BT module for streaming the music is all. That uses a different function (and pairing selection iirc) than using the phone over bluetooth. I *highly* recommend upgrading the stereo (w/ the PAC dash kit). I put a pioneer in that had wireless AA and wireless carplay and it was better than what the 6th gens have.
Any pics of it in your car. How much of a pain was it to install? Sound better? I wonder if a speaker upgrade would be a good idea at the same time.