Default values can change from one code version to another for many reasons. Much like CLI output on many manufacturers, default values usually do not show up in the output of "show run" or show config" types of outputs to reduce the amount of data displayed.
Just a side note. A great command to use in AOS 8 for showing config in the cli would be "show config effective detail" at a a given level. This will show you whats configured at that level, and whats inherited and from where.
example:
wlan tsm-req-profile default # inherited from [/]
!
wlan ht-ssid-profile default # inherited from [/md/Home-Lab]
no 40MHz-enable # /md/Home-Lab/Virtual-Cluster
no very-high-throughput-enable # /md/Home-Lab/Virtual-Cluster
no 80MHz-enable # /md/Home-Lab/Virtual-Cluster