You can find out if your iPhone is an AT&T model. All you need is to check your IMEI status.
Many IMEI checkers will give you model, capacity and color. If it happens yours is an AT&T iPhone, you'll have to go online to request the unlock.
Can i just go and request it myself? I started thinking that this phone is under contract....so what will happen if I will request an unlock?
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Also how can I check whether my phone is not black listed and that Att will unlock it?