Completion date is the date the car rolls off the line but they only show a month and year on the driver side door panel as a manufacture date. I got an email on Feb 17 that my car had been "born" and he gave me a delivery date of march 10.........which is six weeks so my guess is the VIN is assigned early on at the time the body is worked on or married to the chassis. I got my care on March 15th the extra days were port and shipping time. Hope this helps.
Thank you. Means my car is going to be several weeks later than was originally indicated. Ordered March 20 and told 4 months max. Have now been advised build is w31 and given they shut for all of August I'm guessing I may not see my car until Sept!! Communication from dealer very shoddy in my view. Will be giving them feedback in due course!