Mark II serial numbers

[Milsteads Garage]

We have breakdowns on the interior codes which is your 1B6M code. It is a little hard to find on here but 221-6 means the following: February 21st production date: 6 one off the line that day. From what I remember, car 3418 (we categorize and identify them by the last 4 of the vin) was the first 1957. So while yours is technically a 56, many states categorized the year of the car as the first year it was registered, not manufactured. There have been a few cases of owners reporting this over the years.