Assuming that the AFX has not generated a new Hostname because it had a duplicate hostname (it has generated a new one if the hostname starts with a letter from G-Z), the hostname is made up of the back half of the MAC address. So a hostname like AutoFlex-AB12CD would have a MAC address of xx:xx:xx:AB:12:CD. If you can see the hostname in your list of DHCP clients, that should be enough info to know which device the AutoFlex is.