Barsa told the AP that Monroe was poor and desperate for stardom at the time the film was made, but Fortner said that is "inaccurate and inconsistent because she was already discovered and was a well sought-out model."
Barsa Defends That It Is Monroe in the Film
Barsa offered a 1996 letter from Alan Brown, a member of the American Film Institute, which he told the AP confirms that the woman in the film is Monroe. According to the AP, however, the letter reads, "It's not clear whether the woman in the film is Marilyn Monroe -- if not, she's definitely a lookalike."
Bob Gazzale, president and CEO of The American Film Institute, said in a statement that the AFI "does not engage in activities of this nature." He also added in that same statement that "AFI preserves the heritage of the motion picture, honors the artists and their work and educates the next generation of storytellers."
AFI did not respond to ABCNews.com's inquiry specifically regarding Barsa's claim about Alan Brown.
Barsa shared another document with the AP, which he said was a copy of a declassified FBI report claiming Monroe was the woman in the film. The text, which was heavily redacted according to the AP report, refers to information from a third party who claimed Monroe's ex-husband and baseball giant Joe DiMaggio, was offering $25,000 in 1965 for a film that "someone else claimed showed Monroe having sex." The document itself, however, didn't say if the alleged film even existed.
Lois Banner, professor of history and gender studies at the University of Southern California and author of "MM-Personal: From the Private Archive of Marilyn Monroe," said she believes Barsa insists on selling the film just because of the money involved.
"There have been numerous tapes alleging to have caught Marilyn at a particular moment in a particular sexual indiscretion, but I would not accept any such tape without a documented provenance," Banner said. "No one would buy a Miro or a Picasso without such documentation, my understanding is that the person selling the tape has brought none of this forward."
The auction is scheduled for Sunday at 7 p.m. GMT at the Borges Cultural Center in Buenos Aires.