Norma Jeane was not a natural blonde. From childhood to early adulthood she was a Brunette. Only during her modeling days, sometime around 1946, did she dye her hair blonde.
The facts of this film are greatly inaccurate and it should not been seen as an accurate biography of Monroe's life.
Norma Jean(e) Baker spelled her name with an "e" at the end of Jeane. Her name is misspelled throughout the movie omitting the "e" at the end of it.
This actress looks nothing like Marilyn, has no sex appeal and even talks with a lisp.