When we were on the May 24, 2014 Alaskan cruise onboard the Wonder, we went to the Gold/Platinum reception where we could ask questions of the Captain and Cruise Director. One question was, "When will the Wonder undergo the extensive rehab the Magic did?" and we were told not until the new larger locks were done. The Wonder is the only ship in the Disney fleet that can still fit through the original locks. Once the ducktail was put on the back of the Magic, it can no longer fit through the original PC.
This would indicate that once the new locks are open, DCL will upgrade the Wonder, add the ducktail, and begin using the new locks. Perhaps Captain Puckett was speculating about the Dream/Fantasy, which would be a tighter fit in the new locks than the Magic/Wonder. I can't see DCL not using the new locks with the smaller ships. They will want to upgrade the Wonder to match her sister ship, the Magic. They will want to continue to visit the west coast and Alaska. Therefore they cannot keep themselves confined to the old locks.