A glance at the delivery tracker google sheets is a boon for these types of questions. Even from a small sample size, the abrupt change from US customer production to foreign customer production is remarkable. Looks like US cars were being produced up until around 22/23 December followed by an abrupt change to European production (seemingly the factory was not closed last week of December). Many of the cars that were produced in the week up to Christmas were also delivered by the end of the year (US customers).
Okay look at the data sheet more closely, what makes you think there was an abrupt change to Euro production last week and that the factory was open? I don't really see anything that clearly seems to indicate that.