Welcome to MC... Unfortunately, Forgetful Jones is what we tend to call a "retired" character. His regular Muppeteer, Richard Hunt, died in 1992. And most, if not all, of Richard's SS characters have been retired. Gladys the Cow was brought back recently with a new performer, as was the Two-Headed Monster.
You'll have to do some tape trading with reputable members here on the forums to get some classic SS episodes featuring that short-memory ranchhand.
Hope this helps. And have fun exploring the rest of the forums.