You did not mention if this is a built-to-order device? If so, yes, always the case, as Apple does not keep Macs around in all possible configurations. Basically just base configurations.
And along those lines, keeping inventory around costs Apple money. Among the issues, tax liabilities, warehousing costs, cash conversion cycles.
That said, seem to recall a thread where someone mentioned that their base configured Mac was shipping from a US location (poster was in US and not near an Apple Store). So if that was true, also kinda see that as lots of Apple Stores in US and makes some sense to centralize on the west coast some inventory to over-night to the stores across the US. But even then, Apple does try to minimize inventory on hand. As seen in the tracking, takes just a few days for Apple to re-stock their store inventory.