PATS--How do I know?

My niece has a 97 Sable but I'm posting here in the Taurus section because I think it'll get more traffic. Anyway, she lost both keys for the car. It seems that some 97 Sables had PATS and some didn't. Obviously this plays a huge role in how to go about replacing keys and/or ignition lock cylinders. How can I tell if this car has PATS installed on it? I'm sure there must be some marking or stickers on windows or something but I can't find any. It has a production date of 5/97 if that helps any.

Thanks in advance for any help!

Brett

The books says PATS was standard equip on Sable LS & Taurus LX.