Have you ever heard of the Pope Pius XII Hymnal? It’s a real book, published in the United States in 1959. Here’s a sample page so you can verify with your own eyes it existed.
Pope Saint Paul VI (3 April 1969): “Although the text of the Roman Gradual—at least that which concerns the singing—has not been changed, the Entrance antiphons and Communions antiphons have been revised for Masses without singing.”