An acquaintance has a 2016 registered XDiavel, the 10th letter of the VIN is a G which denotes the bike was built in 2016. However it has a 1262cc engine which is clearly stamped into the engine casing, yet the Ducati parts fiches and any other info I can find out says the 1262 engine didn’t go into the Diavel until 2018.
Did an internet search (Apple AI engine based) and it confirmed the 2016 XDiavel has a 1262cc engine. Andy