The 2 Postcards from Big Bird sketches are from the 90s, not the 80s.
Must have been very early 90's. I remember seeing them as a child. Of course, I watched SS all the time till I was 8 or 9. Then I watched thime with my sister who was born in 1990.
Anyway, I will say, they are trying with 1980's segments. Most of them can be aired without being dated, and intergrating with the rest of the show. I don;t think they could get Miami Mice and Lifestyles of the Big and Little to work as well, but a lot of older stuff can work.