After reading this thread and inspecting my phone I noticed the gap and it bugged the hell out of me so I took it back to Best Buy to get it exchanged. If they give you trouble for trying to exchange it because they don't see the gap, ask them for a piece of paper and slide the paper in between the gap on the bad side and then have them try it out on the other side (paper won't fit if the bezel is securely in place). This basically had them acknowledging the issue and replaced mine for free.
AT&T Pebble Blue SGS3
AT&T Pebble Blue SGS3