Question about unknown Farley sketch

[YellowYahooey]

I read on a YouTube video description in a fanmade remake of a Muppet sketch, some hinting that there may have been a sketch where Farley demonstrates the numbers 6 and 9 right-side up and upside down, possibly in the same fashion as Herbert Birdsfoot's infamous M and W lecture. There is obviously nothing on the Internet regarding this sketch, and I do not remember seeing it on the show during the 1980s. Is it possible this segment was rarely shown, and aired only during the 1970s? Also, did such sketch ever air on "Sesame Street"?