Hi y'all, I'm new to the forum and am trying to get my feet wet with learning how to tune myself. My truck is already tuned and I'm happy with it but with the EPA being the way it is I want to learn myself so I can troubleshoot any problems and make changes as I need. I never saved the stock file when I flashed the DSP5 tunes but I got a stock one from someone and the OS is 12628594 which is the same as a couple other tunes I've seen on here. However the OS from the tuning currently on my truck is 11720809. Can someone please help explain what the OS is and the significance of it. I've seen people posting their VIN when asking for a stock file asking for the correct OS. My vin is 1GTHK23608F145363. 2008 GMC Sierra CCSB 4x4. Any help would be greatly appreciated.
-Dylan
-Dylan