The film's final credits do name the character played by Tony Burton as "Price," but this character seems to be based on Robert Otis *Pierce* who was executed at San Quentin on April 6, 1956 and the disturbing circumstances of whose execution as reported in various sources fit in many particulars with what is depicted in the movie. Since the actual names of other real-life persons portrayed in this movie--not the least of which Chessman's are accurately reproduced, it may be surmised that "Price" in the credits is an error for "Pierce."
In one scene the sub-title states it is January 1956 but it shows Chessman arriving at court building in a 1957 Chevrolet which did not debut until September 1956.
Even though it is furled in the background, American Flag in the office of the warden at San Quentin has fifty stars, as it does now, but that flag was not adopted until Monday, July 4, 1960. The flag that should have been shown was the forty eight-star Stars and Stripes, which was valid from Thursday July 4, 1912 to Friday July 3, 1959, and is even seen hanging high in Grand Central Station in Hitchcock's North by Northwest.