I have bought three iphone 4S recently.
1) an AT&T upgraded, discount ($199) contract one (locked for sure)
2) and off contract Device only one (unlocked, still unlocked after upgrade to 5.01, and i think it will be always unlocked for sure),
Both are MC918LL/a.
3) The office unlocked one I just ordered from Apple Store online is MD234LL/a.
So I think the model # really does NOT matter!!! As soon as it is not locked in apple system.
1) an AT&T upgraded, discount ($199) contract one (locked for sure)
2) and off contract Device only one (unlocked, still unlocked after upgrade to 5.01, and i think it will be always unlocked for sure),
Both are MC918LL/a.
3) The office unlocked one I just ordered from Apple Store online is MD234LL/a.
So I think the model # really does NOT matter!!! As soon as it is not locked in apple system.