Radio lock did not set code?

GM used to have radio unlock hotline that you could call, you then entered the numbers you got from the radio and you would get the unlock code. That system was shut down a couple years ago when GM decided that it wasn't getting enough use to keep it going. The codes then fell back into dealer only territory. From LOC you can usually get to the code entry screen by holding down the 1 and 4 buttons, turning the ignition on then keep holding for about 7-8 seconds, you should see SEC come up and then you can enter the code. Getting that code isn't easy anymore though. To get the code you need the radios serial number, the VIN and the unlock ID you already have. Then try a couple dealers, some don't charge while others do. Also if you have the original owners manual the code was commonly in them. There were a few more common codes like 2174 and 2431 but I have no idea if those would work. Be advised that if you enter the wrong code the radio can shoe INOP and then you have to keep the key on but not run the engine for an hour before you can reset it and try again. This is one of the reasons why many remove the stock units and install aftermarket ones. Plus those generally allow for things like blue tooth and more.