Sure. Open the context.php of the old monobook template and insert the following snippet (but remember: after updating monobook, you have to use the way described on the
template's homepage):
//Recent changes
if (!empty($conf["recent_days"])){
$monobook["content_actions"]["tab-recent"]["text"] = $lang["btn_recent"]; //language comes from DokuWiki core
$monobook["content_actions"]["tab-recent"]["href"] = wl("", array("do" => "recent"), false, "&");
$monobook["content_actions"]["tab-recent"]["rel"] = "nofollow";
}
if the code above does note work: post it (I typed it right here, did not checked it on an old installation... if it does not work, there is probably a typo somewhere). ;-)
However: You should really update your DokuWiki and monobook ASAP. ;-)