I have a blog on a related topic of Comcast founding in Tupelo with a 2009 endnotes page providing piece-meal information on the young producer who persuaded Elvis to make the recording. Information is spread over several of the endnotes entries.
The WJOI recording debuted in 2012 in international album of Elvis live recordings. Websites and discussion groups asked "Why did it take so long to surface?"
AEF Eddie and Dottie Foote, Covent Garden, London