I have in the past in a Sydney store, however they didn't know a twin lens camera kit I was trying to buy was on sale and they didn't have it in stock, I had to go to the vodafone store next door and bring it up on a web browser (internet on phones wasn't very good then) and once they saw the special price they made a few calls and ordered it for me.
So yeah can be done, but it all depends on if they know the sale's happening.
Give them a try on the phone, all my local stores have a number on here: JB Hi-Fi Stores
be a great machine to own! those laptops are pure beasts too!