VMS Help NCS Command, Command Qualifiers, /BEFORE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  /BEFORE[=time]

   By default, all definitions in the NCS library are  listed  when  you
   use the /LIST qualifier. However, you can used the /BEFORE qualifier
   to list only definitions created before the specified time.  You may
   specify an absolute time or a  combination  of  absolute  and  delta
   time. If you use the /BEFORE qualifier without specifying the  time,
   the output list will include all definitions in the library  created
   before today.