As is said: the proof of the pudding is in the eating. So let him show it fully works (phone, SMS, 3G data) using, say, his or his girlfriends AT&T SIM-card.
When you're convinced of that, you go to an AT&T shop together and ask them to confirm it.
Question: Are there issues with using a Korean iPhone 4 GSM on GSM carriers in the US assuming its unlocked?
What if it locked? Is there a way around this??
A friend in the military brought it home and want to sell it to me......I just want to know what I'm getting. He says its unlocked but I'm new to all this..and afraid he might disappear before I figure this iPhone out.
Thanks in advance for helping me!