here in the States.. the New year production starts August or September before..
so 9/04 is a 2005 model.....
(Long time ago), my room mate got his next model year Mitsubishi Eclipse in May.
Next year his insurance agent asked him, if he bought a new car. My room mate told him, it's still the same Eclipse, he insured last May. Model year this year, purcase date May of the previous year.