The only certain way of identifying the year of a particular VW 1200 sedan is to check the chassis number of the car in question and to compare it with the chassis numbers listed below. Until 1955, the Volkswagenwerk did not have any "model year." Before that, a 1953 VW was simply one which was produced between Janurary 1, 1953 and December 31, 1953. Since 1955, model years begin on August 1.
What makes identification doubly difficult is that improvements (both exterior and interior) often where made midway in production. The absence of the Wolfsburg crest on the VW's front hood is the only exterior change which sets a 1963 VW apart from a 1962 model. But this modification wasn't made until November, three months after 1963 production began on August 1.