Yep. My first iPhone 4 had a slightly angled power button that did not rattle or move at all, and had a horrendous rattle in the camera (that was definitely defective), but my second one has a completely flat power button that has a tiny amount of side-to-side play in it. It doesn't rattle or anything but it's not as rock solid as the first one's power button.
Every phone is going to be very marginally different. The black that they use to dye the bezel on Tuesday might have been mixed by a newbie and so might end up a little bit more gray. There is way too much that goes into the production of things like this to freak out over marginal differences between them.
You do realize that the dye is most likely not done by actual people, and is most likely done by machines.