statistics monitoring performance improvment -- 8.1 as well as 8.2 ?

Last year, there was a problem involving stats_command_string in early 8.1.x

    http://archives.postgresql.org/pgsql-bugs/2006-01/msg00151.php


I see mentions of performance improvements in the statistics collector for 8.2.x

    http://www.postgresql.org/docs/8.2/static/release-8-2.html

   "Improve performance of statistics monitoring, especially stats_command_string (Tom, Bruce)
    This release enables stats_command_string by default, now that its overhead is minimal."


Did those improvements ever get applied to postgres 8.1.y  ?
perhaps in 8.1.8 or 8.1.9 ?

thank you,
 - Scott Bjerke
   DBA, intercasting corporation