You think? That would be very unusual for Apple to update the Online Store on any day aside from a Tuesday or Friday.
I've always expected to receive launch products on the day, even when ordered online. When I got my rMBP, they were always available immediately after the keynote.
This is the first mac I am buying like this, so had no idea about delivery. Bit disappointed. I would normally just purchase in-store, but as I work in the HE sector, I can get 3 years free warranty uplift, which is only available through university servers.