Further information about the acetates can be found at In Spite of All the Danger.
That'll Be the Day is a song by the Crickets on their album The "Chirping" Crickets. The song was famously covered by The Quarrymen, which became part of the first recording made by what would eventually become The Beatles. The group then composed of John Lennon, Paul McCartney, pianist John Lowe and Colin Hanton as drummer. The song released on Anthology 1 after, along with it's B-side, In Spite of All the Danger.
Paul McCartney owns the Buddy Holly catalogue.