Google Books is your friend, Roy. It's always my first source and it hardly ever fails!
It looks like you have cylinder holddown nut wrenches for the Continental 6-cylinder, horizontally-opposed, four-cycle, air-cooled, supercharged engine with OH valves, with the FSN-stamped example being slightly older than the Snap-on example, which has a later stock number.
Click
HERE and it will take you to my search results. The first TM 9, from 1952, lists the wrenches by the FSN, the second, from 1959, lists them by 7XXXXX stock numbers. Both have diagrams showing the wrenches.