Woodchuck Bill wrote in
:

However, it is still possible to change a moderated group to an
unmoderated group, through the same RFD/CFV process as in creating a
new group.

Note that this is truer in theory than it is in practice. The result
of trying this would be to have the group appear as moderated in some
places and unmoderated in others (and, most likely, posts made on
servers that think the group is moderated would totally disappear).

John