Yup, that’s what probably happened? When a young guy in Dallas totaled his P1 after less than 24 hours of ownership, McLaren built him another but gave it the original VIN so as not to mess up the 375 production limit.
I didn't think there was ever any question that the car would be replaced and quickly under warranty. I don't see this as surprising at all. I can only remember one new car that caught fire and burned up because of a defect during the warranty period during my auto dealer days and it was promptly replaced at no cost to the customer.