[Q]How do I check if the phone I want to buy is FACTORY unlocked (sim free)?

Hello there,
I want to buy the note 2 from a local seller.
Some people warned me of 2 types of unlocked note 2, that maybe i'll encounter.

The first one, is a code unlock, which means the device was locked, maybe bought by some cellular network (at&t, t-mobile and such..) and then was unlocked by a code which was given to the costumer (which means every time you'll update it, you'll have to use that method again).

Or the second one, which is factory unlocked, which of course I prefer, and want to know that I buy.

How do I check which one of those methods the phone has been unlocked with (maybe using the codes on the package)? Internet? Something?
Can I check it even if the package is still sealed?
If the package is sealed, does it mean the device is factory unlocked?

Thank you very much, will really appriciate a quick answer,
orl2008.

If it says Galaxy Note II GT-N7100, it is the International version, SIM Free, factory unlocked. The phones that their model number does not start with GT-Nxxx are not.

Once it is SIM unlocked it is permanent. It will not revert afrer updates.

Pop another GSM SIM in it. Even if the SIM is inacrive it will still show the network. (Emergency calls)

All US carrier phones are networked locked when new.

Sent from my SAMSUNG-SGH-I317