Even within the same plant in the same month there are differences.

Lots of different employees, different shifts, temperature & humidity when the car was dipped, sprayed, etc., etc.

So........

Your car was there when it was built, so it is the best evidence you can find, explore & discover all you can.

Record the details with a camera & start a file.

Document what you find on your own car & then put it back to the same way, anything less (or more) is not a true restoration.