E40 ECU with Wrong OS

I have 2006 Trailblazer SS and was changing the mechancial fan to electric fans. When I was notified the tune file pulled from the vehicle has the wrong OS but the right VIN # that match the vehicle. It appears the OS is for a GTO or impala as far can fnd on the internet. Not sure how this possable. Is there a doc some where that list all OS to cars or Trucks. I was sent a new tune file with the right OS but it could possable brick the computer. So I'm tring do some reach before move forward.

Current Tune Calibration
VIN: 1GNET13H162213550
Operating System: 12604792
Calibration: 12604791
OS ID: AA
BCC: YMUM