I have an economy booking which is now on the A380. Our seat selections are showing as 11A/11B (unconfirmed), which are obviously now not economy seats. I'm not able to change them online though. May have to try phoning up - if there's any possibility of snagging an upper deck seat, that would be nice!
EDIT: In fact, now our seats are showing up as 44E and 45B on BA.com, but 11A/11B on Qatar's site.