As I understand, the Moto E Verizon Prepaid smartphone model XT1528 is unlocked.

Can it be used on a GSM network?

If so, shouldn't there be an option for "GSM" in the phone's settings (in Android 5.1:  Settings / More / Cellular networks / Preferred network type). Right now, the only option available is "LTE / CDMA".

Thank you!