Under the Regs you cannot return an item that has been built to order. If you requested 512Mb Ram instead of the normal 256mb then that would be considered a Special Order and wont be covered. Likewise with Hard Drives, if you asked for a larger capacity then the same will apply.
I would also make sure that they ship the laptops from stock and do not "Build" them to order which so many manufacturers do. Components change so fast that to sell computers from a large stock of identical machines that would enable you to return them under the regs is unlikely. If they were to hold such quantities and the latest "Must have" graphics or CPU came onto the market they would loose out big time with hundreds of machines they could not sell!