Inspired by the pre-war maneuvers.
The first attempts were apparently (at least by the photos below) the gun and it's trail legs-less cradle plopped onto the back cargo bed.
(https://i.imgur.com/ESdiCjL.jpg)
(https://i.imgur.com/qRIwU6c.jpg)
(https://i.imgur.com/rXA5Wa0.jpg)
From what I've read, this was unstable and was followed by a pedestal mount without the M1917 Browning watercooled.
(https://i.imgur.com/qKOv7NZ.jpg)(https://i.imgur.com/14W3iey.jpg)
(https://i.imgur.com/zElM3CF.jpg)(https://i.imgur.com/rbuVbp0.jpg)
That sounds like low-hanging do-able fruit to me.
Chekov's 37mm?
“If in the first act you have hung a pistol on the wall, then in the following one it should be fired.
Otherwise don't put it there.”
https://www.scalemates.com/kits/monogram-8711-jeep-and-37mm-gun--186339 (https://www.scalemates.com/kits/monogram-8711-jeep-and-37mm-gun--186339)
(https://i.pinimg.com/originals/9a/48/1c/9a481ccf3713cd5f84956e3ac8254d13.jpg)
http://warwheels.net/T2-T2E1_37mmGMCindex.html (http://warwheels.net/T2-T2E1_37mmGMCindex.html)