I don't think Apple made many watches prior to. I was a day one delivery for my 42mm SS. When checking the build date, it was the week before. They obviously did not have a lot of stock ready, and now are building and shipping out as best they can to fulfill orders.
They probably already used up the few they kept for replacements (if any), so will have to build a new one for you. But at least you get a brand new watch. 🙂