Well there you go mate, you learn something new every day! I actually remember the first time Lucky Starr sung it on "Bandstand" (if I remember correctly that is)
A little further research shows that Rolf released his version in 1963 so entirely possible for both to be getting radio play back at the same time. Though I admit, well before my time.
Also Lucky had four versions. Australia, NZ, UK and he US on the same EP.