Okay let me lay out the details of a hypothetical situation.
1. I have a 2005 Silverado - Not licensed to the PCM, yet.
2. I have a 1999 Silverado - Licensed to the PCM
Can I put my 1999 VIN number into the 2005 PCM and disable VATs so the BCM won't bug out? This way when you plug the OBDII scanner up it will spit out the 1999 VIN.
If I am missing something or you have any questions let me know.