Perhaps Jeff was sure your car was a 1926 as M came out Jan 1 1926. Having no info on your car. vins are model years not production years and in Billy's empire up to 1930, Aug 1 of one year to July 31 of next year was next years model. So in the case of M production was Jan 1 1926 to Dec 31 1927. You can't use engine casting dates as engines were cast months (or years) before being put in a vehicle. The 614 came out Jan 4 1930 and 22A engines were cast Oct 1929 and up. My 32 castings are April and May 1931. Then there was the 40A cast for the 1931 675 De Vaux, that got used in the 32 680 De Vaux with Hall name ground off and used again for the July to Dec 1933 Ace with Hall name ground off. All 40A's are cast in 1931.
Yes the Model F that went to Dec 31 1925 is different to M with visor, body, splash aprons etc. And yes cars registered after the year are sometimes out a year. That was the case with the late members early 1930 614 that sat in the back of the dealer for months before being sold 1931. He fought with Nova Scotia DOT over that and gave up. So had a plate made to hang on the front of the car saying 1930 Durant made in Leaside Ontario.
Where Are You From? Ottawa Ontario Canada
Do You own a car built by Durant? 1932 614 sedan made by Dominion Motors