Don't know about reports, but your device would be following the locking policy of the original carrier or the carrier chosen during setup.
For instance, my son has a Sprint iPhone 5 (a recent replacemnt for a Sprint 5 with a bad battery). I was given the opportunity to choose the carrier. I chose Verizon. So, now this formerly Sprint iPhone follows Verizon's locking policy.
Since Verizon's policy is to unlock all LTE capable devices this fully unlocked the phone. So, now my son is using it on our carrier T-Mobile.
Are you trying to find out what carrier the device is locked to? Because you aren't the original owner?