Audio Systems: switching radios, 2007 chevy silverado, chevy silverado

Question
I have a 2007 chevy silverado classic, and I put a new GPS radio in my truck and it works fine.  And my wife has a 2005 chevy suburban and her CD player doesn't work.  I installed my factory radio from my 2007 into her 2005, but it's locked.  Is there a way to retrieve the code from my radio while it is hooked up in my truck ?  what would be my best alternative ?

Answer
the only way is the dealer
there is no code the radio works this way

when the radio is power it looks for the vehicle BCM and ask for the vehicle vin number if the vin number the BCM sends to the radio  is not the same on the radio memory the radio will lock

the gm dealer with a gm scan tool will write the new vehicle vin number in to your radio and it will work  
you need the dealer or someone with a gm scan tool