Would Apple replace my iPhone?

I got my iPhone as a christmas present from my parents this last christmas. Therefore, I have now had it for about 6 months. I received the warranty with my iPhone stating that defective phones would be replaced. My phone already has a few scratches here and there, but nothing big. My main issue is that my ringer/vibrate button is loose, and it rattles whenever I shake or touch it. This is really annoying and it really sucks to have in my pocket during school, because the button moves around so much I can never tell when it goes off vibrate mode. It will ring during class if I ever get a text message. Also, I've heard that they give replacement phones to people with bubbles inside/under their screen; well mine has dust inside it that I can't shake out or rub off. It's really honestly irritating to look at whenever I'm on the internet or looking at something with a white background. Would these be good reasons to a Genius at Apple to replace it?