Judging from the Paule Lengellé box art painting, the Heller ship has all the main features that should be found on the Mataro ship, just mounted on a slimmer hull. Still, if Heller somehow managed to make a somewhat proper scale model of an early carrack, they got there by mere accident... and I agree with Mr. Tilley: as for the naming of their ship models, the people at Heller showed a limitless yet clueless creativity.
I remember the Atlantic Carrack ( I guess this was the one based on the Santa-Maria, the "Mataro", judging from the price and box size, should indeed have been based on the smaller hull but I could be wrong here) was called the "Conquistador" -that might have been the profession of those on board, but I highly doubt the Spanish or Portugese would have named their ship like that.
BTW I always thought that the "Conquistador", even though based on the Santa Maria, was a historical reconstruction, simply based on the fact that some Italian manufacturer offered (and still offers) a big wooden model of exactly the same ship (this time more properly named as "Caracca Atlantica") -it even has the same paint scheme! After a little examination I am quite sure that it was the other way round - the wooden model was just a rip-off of the Heller model that was itself just a rehashed version of their S.Maria.
All the former Pyro kits, even the smallest ones got fancy names like "LÓrgueilleuse" for the "Brig of War", "Half Moon" became "La Providence" and even the small "Golden Hind" was changed to "Marie Galante" - some were even named after real ships that looked completely different- they renamed the "Olympia" as the "Maine" (but Pyro came first with that bad idea) and had a "Le Sphinx" that was actually a "Harriet Lane". What fun.
Sorry for straying away from the main topic. As for the "Kanrin Maru", I remember seeing that one on eBay as well. It was indeed 1/100 scale and had a NITTO logo on it. Boxart resembled the Revell Alabama in perspective and general layout if I remember correctly. A shame that in the auction there were no photos of the parts - I´d really like to know it this kit was a good one. It seems it has never seen a recent reissue. The wooden IMAI model is 1/50 and is 127cm long, so the Nitto kit is not that small either.