I recently had an opportunity to purchase a real photo postcard that I think is Patton's first card. As this was super early in his Military career, Patton wasn't even listed on the card.
I found the original image in the El Paso Morning Times: Aug. 26, 1914: Warm Welcome by General Pershing For Villa and Obregon in El Paso. Attached also are the names of all the famous people in the photo/card.
This predates his 1950 Topps Freedom War by 36 years and the US involvement in WW1 by 3 years.