Chosen Solution
The screen assemblies are pretty easy to differentiate. The main difference between the 6 and 6S series is the inclusion of the Force Touch IC (embedded in the backlight shield) and the Touch IC (on the Flex) on the iPhone 6S assemblies. The iPhone 6 assemblies do not have these IC’s. As for the 6Plus and 6S Plus, the same applies. Take a look at the pictures here and here.
