Provided "ADGroup" is an acceptable value to be used as an identity, yes. If you were to add the "-Recurse" switch you'd get the membership if "ADGroup" and the membership of all the groups that are a member of "ADGroup" and all the members of any groups that are members of those groups.
Acceptable identity values are:
A distinguished name A GUID (objectGUID) A security identifier (objectSid) A Security Account Manager account name (sAMAccountName)
Note that the name of the group won't work.