They see more than we do.
My SA told me that they have visibility towards something called a "production plan". They know what will be going into production at what time, and when will they be receiving cars from California (I guess therefore they also know which one might be matched to your order).
I was told by my SA (1 or 2 week ago) that my car should be produced last week or this week, and they are looking to receive it during the week of May 24 and I can expect delivery the week after - obviously with the caveat "these are all tentative".