Yeah I do remember the URL being changed at least once back on the old forums (mind you, I joined in Sept 2011 so I'm still green compared to the old farts of the early/mid 2000s).
Back in my 'early days' (shudder), there was a separate News page run by Mark and I believe the Vault's URL change came about when that News section was folded into the forums. I can't remember exactly when that was, but it was sometime in 2012/13 (maybe mid-to-late 2013), which might be helpful for anyone using archive searches. Now that I think about it, this forum has a fairly interesting history
Before then, I have no idea. There's a Wayback portal to the forums in 2004 out there.
Also, yay @WAtvVideos you're my hero.