I checked at the dealer and they stated that the current part number for the cap is 996 106 44701. but they could not tell me how to tell if I have the "updated" one.
Check your reservoir cap , the blue one in the back trunk, the number is right on it...Make sure you check when the engine is cold, don't want to shoot hot anti freeze on yourself....If that number isn't on it, you have the old one.