Same thing happened to me. Not a speck of dust in between but the bottom is slightly skewed to the left. Hardly noticeable but of course it's bothering me that it's not perfectly centered. It's a bitch putting any screen overlay on a white iPhone and can't see the borderlines.
I ordered another the other day on the 40% off deal so perhaps I'll take another shot at it. I can't help being a perfectionist.
And I tried twice at the button sticker but it's pretty lame. Left it off.
Yay, my little speck is gone, so I guess it was a tiny bubble.