Mike, there are so many variables that no simple answer is possible, as Desi has suggested. You might read the last few pages on each of the top 6-8 topic threads on this sub-forum's list of active topic threads:
Dealers, Purchases and Orders - Ford Transit USA Forum
In particular check out the "Tracking Build Dates" thread, as well as the "Have Window Sticker" thread.
A couple of important threshold questions -- do you have your VIN, and have you been able to pull up your window sticker online?
Generally the experience has been that most dealers do not give you accurate dates, and that it is preferable to do the research yourself using tools and guidance posted here, with your VIN being the starting point.
Before you can actually see your window sticker, any projected build date is not all that reliable IMO, as Ford does not generate the sticker until the factory has confirmed that its inventory of parts will in fact build your vehicle ASAP. If a part is missing, your Transit gets bumped back down the line . . . (IMO)