^ Chrisny good point. Another way to check build date is to enter the last 7 VIn digits into:
http://www.bmwarchiv.de/vin/bmw-vin-decoder.html
As Chrisny stated very unlikely that they would do such a thing. Perhaps asking for the delivery documents to prove that it was shipped directly from the plant would be reassuring. It is very likely a silly software glitch, as how too difficult to match such a custom order. Relax and enjoy.