Launch dates, and what the new stamp actually means
A vehicle carries the date its maker launched it, taken from the maker's own announcement. That date, and not the day we happened to add the page, is what puts a vehicle on the launch tracker and what earns it the new stamp.
It sounds like a detail and it is not. A register that stamps new on whatever it typed up last week teaches a buyer nothing; one that stamps new on what the industry actually launched last month tells you where the market is moving.
Vehicles a maker has announced but not yet begun selling are listed as arriving, with no price until one is published. When the price lands, the page changes from arriving to on sale and the price movement record starts from that first figure.