I have no experience abt this but antiqueshoppers has mentioned that cartier does not authenticate the stuff. But you could call them to ask, hope they would do it for you.
According to Cartier's customer service, they will not authenticate pieces. They also said that they will not service a piece usless you can provide documentation or at least the purchaser's history and explain your relationship to them. (I would imagine if you have a pretty good purchase history with the store/ sales associate, they would make an exception. Unfortunately, I bought my watch from Bailey, Banks, and Biddles over 10 years ago. So, no way they would check mine.)