“The stem scarph is identical to what we know from the plans of Endeavour,” Australian marine archeologist James Hunter said on the group’s website. “It’s also a very unique feature. We’ve gone through a whole bunch of ships’ plans, lots of 18th century plans, and we can’t find anything else like it.”

sounds like pretty good evidence along with the other matching measurements

For more information on the Endeavor, this article sums up its history pretty well, although there are definitely more sources out there with more information: https://newenglandhistoricalsociety.com/captain-cooks-endeavour-world-famous-ship-scuttled-in-newport-harbor-and-forgotten/