/sys$common/syshlp/helplib.hlb PRODUCT, SHOW, HISTORY, Qualifiers, /BEFORE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /BEFORE=time

    Selects entries that were created before the specified date and
    time. You can specify time as an absolute time, as a combination
    of absolute and delta times, or as one of the following keywords:

       TODAY (default)
       TOMORROW
       YESTERDAY

    Refer to the OpenVMS User's Manual for information about
    specifying time values.