Stop in for a cup of coffee

i dont know, we have this problem with one of our tractors. They made it without ANY drastic changes other than little stuff like gear knob size, hydraulic hose size etc, for nearly 12 years. And guess what, the title... doesn't have a year. and no place on the tractor does a year exist either. I was in elementary school when we bought it.
But a tractor isn't a car with proper IDs and registration papers in the glove box and license plates so it's not really the same problem.