Question about an unlocked iphone 4s

[Trihunter3]

I recently purchased an iphone 4s that was stated to be locked to att. ( i am using h2o wireless at this moment)

I am posting this because the iphone was activated by me etc though the phone etc but i noticed if i insert a non att sim for example a tmobile sim card, it brings up a whole new activation screen even though it was activated already.

Does this mean its unlocked or what?

Also when i remove the non att sim the activation screen dissapears.

Any help is appreciated.

I just want to know if ita factory unlocked or not.

P.s i know you can restore and plug into itunes to see if it is unlocked but i do not feel like restoring at the moment.

It is an black, iphone 4s 16gb att

 

[Applejuiced]

If its factory unlocked it will work with any carriers gsm sim.
If it doesn't activate or work with any sim besides AT&T then it's locked to AT&T.