Actually, I believe Givmeabrek meant that any iPhones purchased at AT&T websites or AT&T Store are locked even if purchased at full price. This is true and I believe that there is a 60 day wait period before you can request a unlock? I'm not on AT&T anymore so I wouldn't know how that works.
But yes, AT&T model purchased full price or on iUP on Apple.com or purchased in Apple store at full price are unlocked.