It shouldn't make a difference, they should come back with the same usage window as they had when the reservation was made.
I would revise this slightly, as it depends upon when the reservation was made.
1. IF the original underlying reservation was booked prior to August 3rd, the points don't know where to go back to, so they will go to the use year of the reservation. So if you made a Christmas reservation back in July with credit pooled points with an expiration of May 2018, they will come back as regular use year points with an expiration of Dec 2015 (if you have a January use year).
2. If the reservation was booked after August 3rd, the points go back to the use year they came from. They don't go back to the "contract". I know some had wondered if they went back to the original contract because in theory, as regular points associated to a contract, they would have ARP rights. But the points come back as regular use points unassociated to a contract.
All of that is how it is SUPPOSED to work. Unfortunately, the system is imperfect and has been noted in several threads, points are not always going back to where they are supposed to by policy.