During the early years of Chevrolet truck production the complete door panels were painted sheet metal with no upholstery. The inside window handle needed to be out away from the door panel. This would guarantee that over the years wear in the riser mechanism would not allow the handle to rub on the panel surface as the door window handle was raised and lowered.
To keep the handle secure and better protect the riser mechanism from excess wear, Chevrolet added an escutcheon. This is very important for those reasons.
NOTE: The second photo. The escutcheon is correctly accepting the original handle. This handle is being balanced by a non related fastener.
