[Samba] AD ID mapping back end - must IDs be unique over all objects?

[Viktor Trojanovic]

Reading the wiki page on the topic above, the following doesn't seem
entirely clear to me: must all used IDs be unique, or do just the
user/computer accounts and the groups, respectively, need unique IDs?
Simply put, is it possible that a user has a uidNumber that is the same as
the gidNumber of a group?

Thanks,
Viktor