Here are a couple of 1 1/2 ton GMCs that probably share a lot of sheet metal and drive components except for the engine as your vehicle. GMC used their own engine. The one on with the grain bed is a 1941 and the one with the ladder is a 1946. After the War and possibly during the war the front fenders were made smaller to save metal. Looks like yours has the wartime fenders.
https://photos.app.goo.gl/RP9XiHuvvFrZ9Bu26
