How to identify Factory Unlocked iPhone 4 ?

Really? And what about these models: MC603LL, MC604LL, MC605LL, MC606LL? I know for sure that these models are factory unlocked in the US.

Hate to tell you this, but you're wrong. There is no way to tell from the model number whether it was sold as unlocked or not. The only thing you can tell is that they are from the U.S.

Ok, may be I don't understand smth, but how would you comment this link: http://www.gadgetsdna.com/all-iphone-4-purchases-with-att-micro-sim-coming-unloc ked/11226/

I'd say the article is A) old. and B) incomplete.

The part numbers for locked and unlocked iPhones are the same. There is no way to tell by part number whether the phone was sold as unlocked or not.

hi I just want to ask if how do i check my i phone carrier actually i buy this phone over buy&sell only on netsite.. the only i know this phone come from to canada.. but i dont know if which sim this phone is lock? can u help me wth my problem? ty ^.^