Oh... Well...
"The Letter L" was from this past season, Season 37.
"If I Were The Letter B" was from when the Letter of the Day was presented by Cookie Monster with his letter cookies, not sure if that'd be Season 33 or 34.
Hope this helps.
Oh, and another song question...
There's a song sung by two AM's, one could be called a "City Boy" voiced by Jim with a jazzy sort of singing voice; and a "Country Girl" who sang with a sort of countrified voice, about living in the city and the country before joining in one of those cross-set blendings.
What's the name/title of that song? Have it on my tapes, just don't know what song it is.
Hope to hear from someone soon, have a good day.