If you purchase Unleashed 9U1 part number APs, the firmware will advertise a Configure.ME-XXYYZZ ssid to connect to for management.
If you have two 901 ZoneFlex R500s, you may have to factory default to get access to the WebUI (depending on if they were ZD managed).
If you ever need to RMA one of these APs, you will receive a ZoneFlex R500 again.