I guess it depends. Mine didn't need to change permission since the permissions were copied over.
Here's my host's file permission.
$ ls -al .google_authenticator
-r-------- 1 networkjutsu networkjutsu 129 May 4 2018 .google_authenticator
Here's my Docker file permission.
# ls -al /etc/freeradius/3.0/networkjutsu/.google_authenticator
-r-------- 1 freerad freerad 129 Jun 1 18:38 /etc/freeradius/3.0/networkjutsu/.google_authenticator
It's good to check though to make sure.
Thanks for your comment.