Idle Swede,
I can't explain why your title would be wrong. The MB Data Card is the authoritative document on production date, but I think the sources for our database are accurate. Perhaps the original owner ordered the car in '63 and that's what he had the Dept. of Motor Vehicles put on the title. I don't think those people verify anything.
Malc,
In the US, the "model year" does not correspond to the date manufactured. For example, the 2005 Mercedes Benz E320 CDI is now on sale, obviously built in 2004. Your car was probably built, imported, and sold in 1964 as a "model year" 1965 vehicle. In Europe (and elsewhere?), they did not do this. I don't know the current practices around the world, but 30 - 40 years ago, the Europeans labeled a car by date of manufacture, not by the marketing people's "model year".
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420