I do not know about now. In the past, the status at the time of booking would appear, but you can call MPC to update it before the flight. Alternatively, if the check-in agent is not aware of that, you can ask him/her to check on it and they will be able to print your BP & lounge card with the updated information.

Anyway, as long as the Club miles that pushes your status to Diamond is posted, regardless of what is on the booking and whether you have the new card, CX will recognise you as a Diamond member.