It could have been about any of the colors offered in 1942. Most military cars were chosen of the four door cars available. They could have been any one of the quality levels offered too such as Special, Deluxe, or Super Deluxe. Ford kept manufacturing right up till it was completely halted in early 42. I don't think they would have changed materials for a government contract unless it was specified by contract. Ford was already manufacturing jeeps by that time. Maybe the Early Ford V8 Clubs book for the immediate prewar and postwar cars would have more info.
Just to add:
https://olive-drab.com/od_mvg_vehicle_id_staffcars.php