The model year on a title becomes more and more vague the farther back in time you go. Today it is a bigger deal because the car has to meet whatever that year's set of federal (and state) regulations are, but still the model year often doesn't match the production date year. Back then it really didn't matter as much, the year the car was sold was often used as the model year. If a title was issued at all, not all states had titles back then. And last but not least, Volvo's production runs were not on calendar years, but switched over in (I think) in June.