What about the microphone array (3 mikes)? In the 13" teardown you showed the third mike being out of place (unused). In the 15" this mike appears to be underneath the grille. So there must be three (3) real holes in that grille upper left hand side. I would appreciate if you could show that detail, because it is the first ever Macbook with a 3-mike array. Cool! And based on the distance among each other, it will work for 6-8 kHz signals (hence HQ speech). So expect clear FaceTime and better Siri performance.
I guess the third microphone will become "visible" in the 15" model. In this 13" model it must be switched off (for sure).