That is completely false. There is absolutely no difference between 2004 domains, 2005 domains, and 2006 domains.
There is literally no value to getting a pre-2004 domain or pre-Google IPO domain or whatever conspiracy theory you want to spew out. Please we have enough crazy SEO theories going on without new ones, so there’s no difference whatsoever. Get a domain that works and works well for you and do not worry about whether it was created before 2004.
by Matt Cutts - Google's Head of Search Quality Team