I just received a shipment of used Cisco PIX 525 units and all of them have reversed airflow. In other words the cooling fans instead of sucking cool air through the front bezel are instead pumping out hot air. These units will be installed in the server cabinets with a strict hot/cold rows and I need to change the airflow so that the cool air is directed from the front to back of the PIX unit like the rest of devices on rack. Can I simply open these units and flip the fans around or is this a factory default configuration? I have never seen this on any other Cisco equipment we have handled in the past.