That is an employees plant badge but I am not sure for what year, There are similar ones for Willys Overland, Willys Overland Motors, Kaiser Jeep Corporation and Willys WCD which stood for Willys Carburetor-Dyno Division. There were guard badges with the name Willys Motors and two with Kaiser-Willys also. Willys made many different cars over the years and now survives making Jeeps under the ownership of Chrysler-Fiat.