I am looking at buying a factory unlocked iPhone 4 and my friend told me about her friend that is selling one. I don't know the person and they say it is unlocked, when I asked if it was jailbroken unlocked or factory then she said she didn't know. I believe she bought it from AT&T so I doubt it is factory unlocked. Just to be sure I got the model number, I tried figuring out if it is AT&T or unlocked but couldn't find out. I even called the local Apple store and the guy couldn't tell me, he said he can't find it in the system. Google searching proves there is a model number iPhone with this number but doesn't say if AT&T or not. The model number is MC610LL. If anyone could please identify this for me somehow that would be great.