I suggest you contact the learning institution. My experience is that they sometimes have files of old concert programs (actual hard copies).
They may also be able to contact Buttolph, if living, or someone acquainted with his repertoire (assistant conductor, student aid). If he selected it once, he probably selected it repeatedly.
The university in whose chamber ensemble I sang in 2005-2010 had programs (and even some recordings) going back to the early 1970s at least. The music department may have a separate choral office manager.
He’s passed away now, but I did think about the program idea, next time I’m up there(my mother still lives in that area) I might give it a try.