I am not aware of any means to determine the exact build date of your vehicle. Years ago, I owned a limited edition Corvette that I wanted to track down all the build documentation from the Bowling Green Assembly plant. I used my contacts within GM, to get copies of all the router paperwork used when the vehicle was being built. I did this to establish a complete and total history and pedigree of the car. Even with all that paperwork an documentation, there were no exact dates of builds. Only an approximate date range.
I say that because having worked in GM vehicle assembly plants about the ONLY items in the plant that are tied to a build date and time are any modules that have to be IR gun scanned into the assembly plant computer. This tells the master computer the vehicle X was build with corner module # 123 on this date. This data is used to issue future recall notices (if necessary).
The last time a vehicle (fully) gets scanned is when the vehicle goes through its last inspection called "DVT" (Dynamic Vehicle Test). This is where the " rubber finally meets the road" and everything is tested. Once the vehicle has passed DVT, it basically gets a final inspection, the Monroney Sticker and out to a holding yard (shipped to commerce) awaiting a truck to take it to the dealership that has ordered the vehicle.
So long story longer, there is no real good way to nail down a build date from your vehicle. The best guess (but this could change) is the last 6 digits of the VIN is a build sequence for that model year. 000001 is better than 100000.
