My letter came today also, and my car was a Florida Delivery car. I have since brought it up North to Illinois. So it may indeed depend on it's delivery State. (south and hot)
It also appears, according to the letter, that if you get this letter, and are having no problem with the adhesion "yet", there is no rush to have this done. I also would assume that this warranty extension is Vin # related, and therefore, would transfer with the car, to a new owner. (But that's just an assumption). So if you've recently purchased a roadster, call Chrysler to see if your vin # may be covered.