The Harrigan papers, scripts, songs, etc. are archived at the New York Public Library. "Dunderbeck" is attributed to Harrigan and Hart and Braham, but not with certainty; the papers should be examined for the song. I doubt that any copyright still is valid, but they should be able to tell you at the NY Library.

As posted above, music was printed in Carmina princetonia, 1894, music essentially "Son of a Gambolier." The text had appeared in a Songster in 1876. Copyright Martin R. Dennis, 1894, in the Carmina sheetmusic, but he was a publisher of Carmina princetonia and other songbooks and the copyright would cover just his arrangement and printing.