My wife and I used to watch a lot of old movies. One we watched was from 1954 and called “Secret of the Incas”, starring Charlton Heston. About the third time we watched it I noticed the similarities of his costume with that of Indiana Jones. I looked it up on wikipedia and the costume designer for Raiders of the Lost Ark said she got the idea from the old Heston film.
This taken from wiki:
“Influence on Raiders of the Lost Ark
Charlton Heston and Nicole Maurey
The film is often cited by film buffs as a direct inspiration for the Indiana Jones film franchise, with many of the scenes in Raiders of the Lost Ark bearing a striking resemblance in tone and structure to scenes in Secret of the Incas. Throughout Secret of the Incas, the main character, Harry Steele, can be seen wearing what would later become known as the “Indiana Jones” outfit: brown leather jacket, fedora, tan pants, an over-the-shoulder bag, and revolver.[14] The character also sometimes wears a light beard, unusual for films of its time, and there is a tomb scene involving a revelatory shaft of light similar to the “Map Room” sequence in Raiders.
Raiders’ costume designer Deborah Nadoolman Landis noted that the inspiration for Indiana’s costume was Charlton Heston’s Harry Steele in Secret of the Incas: “We did watch this film together as a crew several times, and I always thought it strange that the filmmakers did not credit it later as the inspiration for the series” and quipped that the film is “almost a shot for shot Raiders of the Lost Ark.”[15]