Two different designs of inside door handles are seen when looking at 1939-46 Chevrolet and GMC trucks. This photo shows the attaching portion is the same. However, the opposite ends are much different.
1939-40 ‘ Small Ends only GM produced this 1939-40 handle design until NOW. NOTE: Even GM later replaced these with only the later design.
Available August 2015, Jim Carter Truck Parts will have them in stock as part # DPH101.
1941-46 ‘ Large Ends. This allows the palm of a hand to better push the handle down and open the door. (A later aftermarket company also produced this 1941-46 style).