That's pretty fast but it can happen. Especially if you ordered very popular options. I've heard of cars with popular options being built faster, but it is an illusion. What usually happens is that a dealer has an allotment that they've already ordered and it closely matches what you want (or exactly matches) and they bump you up in line, replacing their allotted car with yours (since it is already sold, this is in the dealer's best interest to do this).