It sounds to me as if both folks are talking about the same thing only they're each giving it a different name. The door lock actuator is a motor of sorts (rather a solenoid but works under the same principal as a motor). Either way, there's only one electricly operated linear actuator in your door, despite what folks choose to call it. The only other "motor" in your door is a rotary actuator and it's for the power windows (if so equiped) and wouldn't have anything to do with you door lock.