i bet if u order today, the software update will released before your mac is shipped.
i hope so, ill be ordering in about 12 hours!
but I am unsure, as about 14 months ago i ordered an imac where a newer version of the os had been released, and when it arrived it still had the older version of the os installed. what made this worst (at least in my mind!) was that the imac was something of a dud, and i sent it back (ended up getting a mbp by the way, a much better choice retrospectively!)