IPhone 3Gs in two different boxes?!

If its from the USA its certainly NOT unlocked - all US phones are locked to AT&T and cannot be unlocked.

Unless you purchase from an authorized source, and in Saudi Arabia that would be Mobily, there is no guarantee that what you buy is real. Fact is, there are fakes out there.

I'm betting that the shop is selling fakes. Go to an authorized seller in your country and then you know you will be getting a legitimate product.

The difference sizes could also be due to the different power adapters provided with the iPhone.

But it does sound fishy to me!

Try putting the SN in here, see what comes up:

http://www.chipmunk.nl/klantenservice/applemodel.html

Looks like you're good to go.

I also should add here, to close this thread so to speak, that while it appears that you have a genuine iphone, unless that phone came from Italy, it most likely was hacked to make it unlocked. While unlocked phones are sold in Italy, no unlocked phones are sold in the US. You should also be aware of the fact that warranty & support for the iphone are only provided in the country the phone was originally purchased in, and that that warranty starts on the day of purchase, not the day you purchased since you bought from an unofficial source. If your phone was hacked to unlock it, that warranty has been voided & any attempts to upgrade software or restore the phone will re-lock it to the carrier it was originally locked to. Those are the risks you take when you purchase from an unauthorized source.