I've always been interested in the '41 war games, basically the last prewar maneuvers.
Lots of aircraft with unique markings.
Many Don't know the Marines took part with a F4F Wildcat unit.
A popular image of the maneuvers is this rare color photo of an Piper grasshopper getting fuel at a rural gas station as horse mounted Cavalry rides past.
The old meeting the new.
Within a year, the Willys MB "Jeep" was just entering production, the days of horses with scout forces were numbered, replaced by the Jeep and the grasshoppers.
The photo caption says it is from the Louisiana games in which case it would be a YO-59.
If you look closely, you'll see yellow paint under the OD finish and inside the cockpit door.
Perhaps the YO-59s were literally "off the shelf" and not fully painted in Army colors?
Here is a recent university article from a Texas university..
https://www.sfasu.edu/heritagecenter/9595.asp