If you receive 2 codes like so:
“10740919 51393112”
code1: 10740919
code2: 51393112
———- Code Input Instructions ———-
1. Turn on phone with a non accepted SIM card
2. Phone will prompt you for unlock code
3. Enter unlock code1
4. Your phone is unlocked!

If the phone does not accept the code, then you need to do a Factory Wipe on the phone to get it to work. It is a known bug with some versions of the MotoG software.