Does Memphis, Tennessee actually have a Propane Hall of Fame, or did the writers of 'King of the Hill' make it up for their recent storyline?

The Propane Hall of Fame appears to be fictional.

King Of The Hill, the master of simplicity, once again presented a relatively enjoyable story, if not super interesting at every moment. It's hall of fame time again (another advantage of having all four shows air in the same night is seeing the many crossovers I'd imagine are mostly accidental), and Hank's boss, Mr. Strickland himself, is being honored at the National Propane Gas Convention in Memphis. Upon arriving at said shindig, though, Strickland learns that, in fact, there's another Strickland in business—someone who just so happens to be his long lost bastard son, who is looking to reunite, like, now. That means booze, women of "questionable moral character," and hookers. Problem is, Hank needs to keep Stricky in line.

http://www.avclub.com/articles/take-my-life-pleasewhat-happens-at-the-national-pr,23836/

Canada has a Petroleum Hall of Fame. Close, but no cigar.

http://www.highbeam.com/doc/1P3-79147798.html