The wiki may have more complete guides than ever before, but it's still missing complete guides for seasons 2-9 and 14-19, so those could have aired in those episodes. The Herbert Birdsfoot one is from around the second season, I suspect that might have aired a bit more during the 1970s.
I did find out that some guides for Seasons 14 and 15 are completed, but nothing much from Seasons 2 through 9 at this point, though there are some guides from Season 2 published, including the one with the first appearance of the Herbert Birdsfoot "M and W" sketch.
And I believe that particular segment was the very first sketch involving a camera rotating 180 degrees. It's slower rotation was probably designed to make it sound like some off-screen guys was rotating the set, leading viewers to think that someone like Biff and Sully may have rotated the wall along with Herbert and the very stubborn M.
That segment also paved the way for other "upside down" sketches, such as the blonde Anything Muppet girl and the upside down number 11 segment, a skit involving two Anything Muppet boys vs. an upside down 8, and also "Upside Downton Abbey". I know the 8 segment had no rotating camera, but did "Upside Downtown Abbey" have a rotating camera angle?
I also wonder if "Beep" was shown more in the 1970s than in the 1980s? I do remember seeing it in 1982 and by spring 1983. I do not recall seeing it afterwards, and I stopped watching a couple of years later.