Was Bill Lee the singer?

The singing of "Oh Shenandoah" at the opening credits is the best part of this movie for me. I wonder if this is another instance on the great Bill Lee carrying the day without getting proper credit. Or is it some other singer? Anyone know?
http://www.imdb.com/name/nm0496884/

He dubbed John Kerr in South Pacific (although John did a mighty fine job of lip syncing) and Christopher Plummer the Sound of Mucus, among many others.