Lewis died in the magical year, 1963, so he would have been aware of the Beatles but not yet as a global phenomenon, solely a British and continental European one. Tolkien, otoh, survived him by a decade, so he not only lived through the Swinging Sixties but even outlived the Beatles as a band, and that is so weird to think of, yes. :) (Also for a nanosecond the Beatles contemplated playing in a film version of Lord of the Rings. John wanted to play Gollum.)