Eminence has also changed their drivers, so it isn't just the measurements that are different. They have maintained compatibility with earlier models, but they have made improvements that increase power handling. The voice coil manufacturing process has been changed, and so the new drivers are different drivers. Three models of the π Speaker line needed a slight redesign as a result.

The difficult part is knowing which particular motor you have, since there is no part number change to identify it. I think it's a safe assumption that if it has the old label and spec sheet, then it's the old part.