No, there's nothing about that in the notes. It just talks about the history of Kassel, Mahler's time in Kassel, and the performer biographies.
It sounds like glitchy early digital, but it was recorded in 1991. It's just kind of odd. The performance itself is exciting enough. I'd recommend listening on Spotify before doing any purchasing.
If anything, I'm more looking forward to Fischer's Düsseldorf M2 now. The Kassel M1 is 58 minutes (versus 52' with Düsseldorf), and this Kassel M2 is 82 minutes. Given his recent single-disc M8 and M9, I have a feeling the Düsseldorf one will be fleeter and highly detailed. The same probably goes for the future Düsseldorf M6.