Nice pics of the SCR-193 radio in a M3A1. The Chest looks to be a original steel one, most of the Chests you see are repro made from wood, the wooden version seems to be for the ground station setup but I have come across contemporary pics of Dodge CC with the wooden Chest fitted so who knows.
https://handcartz.smugmug.com/1942-M...3A1-Scout-Car/