So as I'm prying the plate off a tiny little nut falls out. I've repaired 4 iPhone 4s now and this is the first time this has happened. Anyone know where exactly it goes? I'd upload a pic, but this forum doesn't support images I see. I'm pretty sure it goes to the long bolt at top center, but where in the stack it goes I'm not certain.

Any thoughts on what the logo is made of?

I'm looking at my new wake/sleep/power button/sensor/ribbon and there appears to be a black pad over the proximity sensor. Not sure if it's a protective cover or if it is actually supposed to be on there. Anyone know?