I'm planning to buy a used SIII through a local website that offers a space for people to display ads for their phones (something like Swappa), but the problem is that I have seen many fake products which looked exactly the same and even have TouchWiz on JB. What's more confusing is that most of these products have a printed valid IMEI number.
I though I might compare the valid printed IMEI with the one I get when dialing *#06#, but I'm not sure if that number can be faked as well.
Any advice on what to look for when examining a used SIII?
PS: I will have physical access to the phone before buying.