The Donahoe's Magazine advertisement notes that 'The Irish Singer's Own Book' has "600 closely-printed pages" . . . the book I have is nowhere near that long. However, the 'Wearing of the Green Songbook' listed directly below with "green cloth, gilt back" may be the one. Which would at least date 'Skibbereen' as early as 1880.

And thanks for pointing that out, Mysha, I looked right past it.