http://web.archive.org/web/200010170...sp?SpellID=322
Says the same thing about the change on the October 2000 archive, so that would imply that it meant March 29, 2000 (the very first patch after Kunark launch, even though those patch notes expressly say there were no changes made to spells other than resurrection and fear- but at that point there were no 60 wizards to notice the changes). There was also no patch on EQ Live March 29, 2001.
Here you can also see Sunstrike is 450 damage in the Wizard spell list on Dec 10 2000 from the same site you linked:
http://web.archive.org/web/200012100...p?Class=Wizard