Could this be a 596? It has 11 holes perfect across the top? I pulled it into my Illustrator and did a rough measure on the photo and it is about 19.25 by 22.5 (ignore the camera distortion). When I count the holes I see 11 perfect holes from edge to edge on top, and 11.5 perfs on the bottom. The sides have 13 or maybe 13.5 depending on how you count
Found on a postcard
