Gary Cooper As Lou Gehrig-First Time A Film Was 'Flipped'?

http://www.nytimes.com/2013/02/09/sports/baseball/researcher-concludes -pride-of-the-yankees-film-was-not-flipped.html?ref=sports
Flipping lets you subtly change the impact of the visual image. If the movie shows motion, having it move from left to right makes it seem natural (since we read from left to right). Flipping the motion so it moves right to left will make the motion seem slower. Similarly, having a spokesperson on the right side of the screen is a stronger visual position than having him on the left. You can flip just sections of a movie, too, which gives you greater control over the final product.
Was "The Pride of the Yankees" the first film, or at least, the most know film up to that time, to be "flipped?"