"In 1948, John Andrechyne Laflin, who claimed to be a great grandson of Laffite, claimed he inherited a trunk containing a journal written by Laffite himself . According to the journal, Laffite retired in the St. Louis area and changed his name to John Laflin, married a woman named Emma Mortimer, had children and died in 1854 around the age of 70 . The paper of ink were determined to be of the period by the Library of Congress, but is felt to be a forgery by John Laflin himself due to the handwritting and Laflin's connection to other forgeries . It has not definitaly been determined if it is a hoax or not. Perhaps they can obtain some dna from Dominique You tomb above and compare it to relatives of Laflin . Doubt that's going to happen."
I'm not sure about Laflin ever admitting that he felt the memoirs were a forgery. I know I've never seen anything in that regard nor ever heard of it from a reliable/credible source. I do know several different attempts were made to authenticate the memoirs and this proved inconclusive, not due to the test but mostly due to a few key people who had their own reasons for discrediting the memoirs. This prior testing, and the circumstances surrounding those test is fully explained in the beginning of Gene Marshall's translation of that full text. In modern times there are still some forces at work that do not want that testing to be done for various reasons. I wish they would conduct these test but given all the modern day agendas and tug-of-wars, just as the above summary says, I doubt that is going to happen anytime soon. This is why Jay, myself, and a few others have undertaken the task of trying to verify or discredit everything we can in those memoirs.