Yes, that is why I posted the question. It would seem that manufacturers would have "model years" So a car built in late 2019 might be the newer body style, etc compared to the same car built in early 2019. In the USA the one built early in the year would have a 2019 Title, the one late in the year after the manufacturer changed model years would have a title of 2020. The year of first registration means nothing. A dealer could have a car on its lot for 3 years using it as a demo vehicle and not registered. The fact it was just sold and registered would not make it a current model year car.
Seems like the car book would be the controlling instrument but cars built late in a calendar year would not have any way of being shipped and sold before the start of the next calendar year. That is why the USA typically cuts off typically in September or October and cars built after that model changeover date bear the next calendar year. However when they do that, any features of the next model year are incorporated into the ones built late in the preceding year. One minor example might be color changes or perhaps different alloy wheels. Those built early in lets say 2019 get the old style wheels and color options, Those built after lets say October 1, get the newer style wheels and color options.
Here is Thailand it seems to be a pattern to call the car the year it is first registered even if that car was built some months if not years before. i saw one car that was labeled a 2018, when I inquired as to why it appeared different than other 2018 models the dealer told me the car was built back in 2015 but only sold in 2018 and that was the older style.
Seems deceptive.