I understand you are. And I believe the Series 7 has the same coatings as the Series 6 as it doesn't make much sense for Apple to change them.
Anyway, I honestly can't be bothered arguing this anymore as it is going around in circles. I believe Graphite is DLC and until someone does a full materials analysis on it in a laboratory, I won't be dissuaded of that. So if I was in the market for a Graphite Stainless Series 7, I would not be at all worried about the durability of the case material. Your mileage may vary and if you feel differently, more power to you.