In the past prior booked reservations earned the MQM's. The one thing I always had to be careful of was my earning preference. My profile is set up for the bonus Hilton points instead of airline miles and even though I would go and change it to delta miles on my profile, on any previous booked reservations it wouldn't reflect Delta and I would have to call the diamond desk and have them change the reservation or remember at check in at the hotel to ask them to change it to Delta for the partner (I found it was better to call the HH diamond desk because it didn't always get changed correctly at check in). One other thing to be careful of with this promo is if you use HGVC. Every year I always have to call the diamond desk to have the MQM's added on HGVC stays.