The group ID isn't very useful in GNO, since there isn't really any security to speak of. The new user has been created. If you log out of gsh using the exit command, you can log back in as the new user. The new user can then use the passwd command, if they wish, to change their password, edit their gshrc file, and so forth to customize their own setup. There isn't any.
Users have access to each other's files, and can tamper with the system files.
So don't expect to use your GNO passwords to lock anyone out of secret data. At this point you should have a basic GNO installation up and running.