I had an unlocked phone with that model number. But then I'm reading somewhere else that the model numbers for iPhone are A1522, A1524. So which is what? What does it mean?
Think of the A1522 and A1524 as being a generic model type.
So the A1522 would be a GSM version covering iPhone 6 plus.
A1524 would be a CDMA version covering the iPhone 6 plus.
Now the MGAULL/A is the specific version of the A1522 that would tell you the color and memory option and if its an ATT or Unlocked.