Hello, I just picked up a starter for my Challenger and I'm trying to figure out the date coding. it's a 3 digit code "190" which I'm guessing is the 19th week of 1970. If this is correct, how were the weeks assigned? For instance, the first week of 1970 only had 3 days in it: Thursday through Saturday. Was it those 3 days that were counted as the first week, or was it the first 7 days and then the next 7 days from where that ended, or some other way?