In 1966 the January 1st (a GM Holiday) was on a Saturday. Anyone know if Fisher Body started counting weeks with the 2nd ? If they made the 1st the first week then there would have been six weeks in January (31st was on a Monday). Reason I ask is the data plate on my Willow Run car says "01B" and I would like to know if "B" means the week of 2nd-8th Jan or 9-15 Jan. Padgett