First, I too have seen the downloads page say an older version...even when a newer version is out. If I reset Safari, sometimes it then shows the correct page. Then, it will revert to the old page, but if you keep hitting it, the newer one shows up. This ONLY happens on the same day as a release. It seems sometimes, the update page shows the older version for a short time. I too thought I was going crazy. This behavior always seems to happen on the day of the release.
Second, whenever I manually install something in SL, then open Software update, it never lists the version number there. Like I said, the version number is missing but the name of the update is there. I read someone's explanation of this a long time ago on these forums. There is a way to edit some file somewhere to add it. But, it's not that important to me. But, I wanted to confirm that not seeing a version number from a manual install seems to be normal.