I'd read years ago that Charlie thought calling the actual devil "son of a gun" was kind of mellow, so went with SOB. In my area, WMEE, Fort Wayne flipped from AM to FM when "The Devil" was topping the charts. On the AM,they ran the "Son of a Gun" version but once the flip to FM happened, they. played the SOB. The AM launched a country format at the same time and they still played the Son of a gun lyrics.I had never heard that story nor the clear punch-in on the album. The story I'd read, in an interview with Charlie, was that SOB was the original as they recorded the album, but they realized they likely had a hit single on their hands, so they re-recorded that one line for the single release (not just a radio version, but the commercially-sold single).