Songtitles starting with U supposedly recorded by Elvis

Uncle Pen
Composed by Bill Monroe
Supposedly Elvis recorded this song at Sun Records but no proof has been found.

Until then (a.k.a. Until the day God calls me home)
Composed by Ray Price
Elvis sang this song live in Las Vegas, December 11, 1976 midnight show.
You can hear it on the unofficial LP Long lost songs and concert cassettes.

The U.S. Army Air Force Song (a.k.a. The Army Air Corps Song)
Composed by Robert Crawford
Off we go into the wild blue yonder is a line from this song, which Elvis sings in the movie Elvis on tour.