Yes. I have to agree with that. Those T&Cs were not made obvious prior to, or at, point of sale. They only became obvious after the pre-order purchase was made. Very obvious after taking our money. Makes me think there may have been a lack of up front and clear info with the T&Cs prior to checkout. It may have been there but they certainly didn't point it out so clearly during purchase as they did post purchase. Like you though, if they do try and charge more just prior to dispatch I'll certainly be doing a bit of investigation on when and how these T&Cs were introduced.I'll probably have to cite a credible source of web archiving where those terms weren't laid out when I bought mine. It looks like they updated their pre-order page with that caveat of price going up and couging up the difference.
On the other hand, if the purchase price is honoured then all's good.