This will tell you... https://www.ducatiforum.co.uk/threads/whats-the-difference-gen1-and-gen2.39606/
2015 MY was the Gen 2 - can't you tell from the link above? Gen 2's will have been manufactured from late 2014 build dates or this article... https://www.cycleworld.com/2014/03/...first-look-review-photos-specifications-video
if it helps I have just sold My Rocket Roadster to buy my Diavel, before that I sold a Thunderbird and another Rocket 111.