^Nick actually changed the date and post dated that BitGold article to make it look like it was posted in 2008 a couple of months after the white paper. The url still says 2005 as you can see in the link you posted. This is also confirmed in emails from Hal Finney.
To me, that's not very good evidence. Why would he post-date it solely to throw people off if you can see the real date in the URL?