Unfortunately, sunglasses weren’t introduced in the United States until 1929.
However, Tarantino purists may argue that the glasses are just one of the many anachronisms that are used in the film that was never designed to be completely historically accurate in the first place.
Another example is the use of dynamite which is featured several times throughout the film. Dynamite was not invented until 1867 by Alfred Nobel who is also the man responsible for establishing the Nobel prizes.
Tarantino’s homage to the spaghetti westerns of the 60s was surrounded by controversy following its release due to the characters use of racial insults and excessive violence. However, movie fans flocked to their local theatres and the movie is Quentin Tarantino’s most financially successful project to date.
Actor Samuel L. Jackson even came forward to defend the directors choice of language claiming it accurately represented what would have transpired during that period. The movie’s soundtrack is also laced with musical hits by everyone from Tupac to Johnny Cash, despite taking place a hundred years before these people were born. Some things just call for suspension of disbelief.