Somewhere in my ancient emails is one from a descendant of Harrigan / Braham who mentions a private phonograph record in the family of an ancestor who as a child in the 1880's had a child role in one of the Harrigan / Hart shows and made the record of his song in the 1950's as a senior citizen. If true, I figure it's likely the oldest show represented by an original cast member recording, even if the recording came 65 or 70 years after the show.