Well, for years somebody (was it more than just one fan?) had speculated that the season one credits crawl included in Old School Volume 1 was taken from the fifth episode. Turns out whoever thought that was correct.
And so now it makes sense why Old School Volume 1 doesn't show the sponsors with the credits crawl: Turns out that they did something different with the pre-credits sponsors the first time: Each letter was announced one at a time, and each letter announced was followed by a letter insert. For some reason, the number sponsors were not mentioned. With that in mind, it makes sense that we didn't see the sponsors included on the DVD... But after the credits is something that was cut from the DVD credit crawl: mention of the book read in that episode (which makes sense, probably rights issues).
By episode 115, the letter and number sponsors are announced the usual way before the end credits, without each sponsor being followed by a segment. Hopefully the guide for episode 10 will be presented soon and we'll know if they continued that the next time they had end credits.
I was looking at the CTW Archives "first season show content" on Muppet Wiki and saw that episode 15 has a few rare segments I have been really interested in seeing/knowing about. But the person who obtained these rare episodes only got episodes up to episode 14. So close and yet so far....
It is interesting to finally see what "Brotherhood of Man" is like. The first season show content document listed it and also mentioned "block party", which got me interested in knowing the context, and now I know that it was originally part of a street story involving a block party. It looks like that is the first time we see Muppets behind the fench between 123 Sesame Street and Hooper's Store, and the first episode to include nighttime on the street. I wonder if that's the first to use the nighttime version of the closing theme. And yet with the episode involving a block party, it's a shame they didn't include Ernie, Bert, Kermit, and the monsters (just Anything Muppets) in the street scenes (unless the guide is just leaving out any mention and photos of such). In fact it would have been a great opportunity to include Buddy and Jim on the street.
It's also interesting to know that the first season had two covers of Up, Up, and Away. There's one time when it seemed to be a film of sort, and the CTW Archives material lists the song as a Muppet segment as well.