I think it is from the VIN. I'd like to know too. I could swear there is a web site somewhere that lets you type in your VIN and tells you everything. Ford has a site where you can type in the VIN but it only tells you what kind of car you have as if you didn't already know.
Anyone out there who can help?
Your dealer should be able to tell you. But there is a way to find out without going to the dealer. I know there is.