I can even tell you the exact date that the change happened as it is on the ordering procedure. There will be a copy of this info in my book when it is done. What you'll probably find is that the change didn't happen on the same date at all plants. The date is September was the say the revision made it into the ordering procedure so that dealers and buyers knew of the specification change. There would have been some cars half done waiting for something so it is possible they weren't finished until early October.