Dear Ed,
I think the tune may be older than O'Carolan, but I have no basis of fact for this theory. I do know that J. Scott Skinner had a version of "Wounded Hussar" in his HARP & CLAYMORE book. There's also a version with a slightly different B part in Tomas O'Canainn's TRADITIOINAL SLOW AIRS OF IRELAND on Ossian publications. It's a great tune, I play the Skinner version on guitar.