Almost all of the costumes are obviously brand-new, with no attempt to age them. This is particularly noticeable in the first scene, with the close-up shot of the chaps, which had supposedly had at least two years' use.
The fingerpicking style of banjo playing in the soundtrack did not exist until Earl Scruggs invented it in the 1940s. Up until then, people used the "claw hammer" style in which the upper strings would be struck with the thumb and the other strings strummed with the fingers.