The last time we visited High Time it was newly revived in 1976. Obviously the band had changed a lot from 1969 by that point, but this version offers an interesting contrast to that one.
I don’t know if calling High Time “peppy” is ever accurate, but the 1976 version likely is compared to how the song sounded in 1969. Even by the time it was recorded for Workingman’s Dead it has gone through a metamorphosis of sorts. But in late 1969 the band was clearly in a transition period and you can really hear it in the music. As their songcraft improved, the challenge became transitioning from deep psychedelia to the more structured environment of folk music (It wasn’t considered Americana at that point. Perhaps folk rock would be a period appropriate term for the band’s musical direction?).
Regardless, I feel like you can hear that challenge unfolding as this song progresses. The Dead had been playing High Time live for 6 months or so at this point, and it’s still quite protean, loose, and sparse. Not bad, just different!