In two-shots of Andy and Jim playing "Midnight Special", Andy's ankles are crossed, but in group shots his feet are spread apart.
The first time Jim Lindsey plays his guitar, at the beginning of the episode, his guitar sounds like an electric guitar but is not plugged into an amplifier.
When Jim is playing in the Courthouse at the end of the episode, there clearly is the sound of a bass guitar and a full band accompanying him, but none is present.