i reserved my 6S Plus via the Apple Store app for reservation pickup. Had to choose carrier and chose AT&T. Picked it up and paid full price since I wasn't eligible for an upgrade after buying 6 Plus last year at subsidized price. Am I correct in assuming since I paid full price my phone is unlocked? And my old phone which I took sim from and put into 6S+ is still locked (I sold on CL) for the person who bought it? Or is the fact I chose the ATT variant and not one called unlocked mean my phone is locked??