Joseph Smith at one point thought North American Native Americans were Lamanites. At another point, he thought Native Americans in Central America were Lamanites.  Other Church leaders have widely varying ideas about which tribes are decended from the Lamanites.  If there had been a revelation on that point, there would not be widely varying ideas.  What we do know is that the Book of Mormon says there is a cave with vast numbers of plates in the Hill Cumorah. There is no cave, and no plates, in the New York hill. The Hill Cumorah in Mesoamerica is many times larger, has many caves and has not been explored.  The Book of Mormon says Hill Cumorah was by many streams and fountains of water. This describes the Mesoamerican hill, but not the New York hill.  Over 1,100 years elapsed between the end of the Book of Mormon account and Columbus voyage to the Americas, enough time for inter-marriage between Lamanites of Mesoamerica and numerous North American Tribes. Columbus never touched foot on North America.  His voyages were all to Mesoamerica.