Wireless Radio Mode ‘gnax’ with E-Series?

Via the device built-in graphical user-interface (GUI), I am able to set the mode of the wireless radio to ‘gn’. That works; even the default management Wi-Fi beacons go up from 1 Mb/s to 6 Mb/s. There is no mode ‘gnax’. However, via the command-line interface (CLI), I am able

(config)# wireless radio 1
(config-radio-1)# mode gnax

If I do that, my E410 (firmware 6.5.1) – which is a Wi-Fi 5 access point – is not gn-mixed but g-only. On air, both ‘b’ and ‘n’ are disabled. Is that intended?