[AC Question]

AT&T S3,
Android version 4.4.2

I *think* I may have, at one point in the past, used the service menu trick to unlock the phone but I can't bloody well remember. I've put a sim card for another carrier in the phone (simple mobile) and I wasn't prompted for a network unlock code, however, the phone is in "emergency calls only" mode. Granted, the sim card is unactivated.

Is there any more conclusive way I could tell if this is unlocked? My primary interest is that I will be travelling shortly and would like to use a destination-local sim card.