Some dealers will "order" a vehicle for you. Which means the dealer is swapping an allocated vehicle with one that is either scheduled to be built or is in transit, or on another dealer's lot. This isn't hard for the dealer to do, but they have to want to do it.
Some dealers operate on an allocation only basis, meaning they are only interested in selling what comes off the car carrier when it arrives. Some however are interested in selling you exactly what you want and as such will go out and acquire the specific vehicle you want.
You may be able to convince the dealer you are working with or any other for that matter if you specify that you are interested in having them do a dealer swap, or finding one that is still in transit and having it earmarked for you.