Not true. The song in question was recorded by Johnny Rebel, NOT Johnny Horton. This has been wrongly attributed to Johnny Horton in numerous publications and on the internet, but it isn’t true. Here is a good article on this confusion: http://www.spasticmonkeys.com/lileks-blew-it/
Well that’s good to know though it is still being attributed to him on sites like Last.fm. You would think if he had family they would still try to defend his name.