Gen. 3717 is double AR coated, as You can read here
https://www.iwc.com/index-en.asp
....Convex sapphire glass, antireflective on both sides and secured against displacement by drop in air pressure...
I was at my AD and compare those two watches side by side, and rep. AR is NOT EVEN CLOSE to genuine so please stop....
On this pic. You can notice how strong blue/purple tint is