I don't know if it'll help answer your question; but in Firefox you can right-click on that page and select "View Page Info" from the context menu where, under the General tab, it says the page was "Modified: Tuesday, July 15, 2008 9:32:56 PM". I have no idea if that just means when it was created, or if that's the last time it was updated.
Edit: I'm thinking that's the last time that page was updated; I just opened a bunch of different websites in Firefox and right-clicked their pages to look at the "View Page Info", and they all returned the current date and time.
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