I wonder if it has been rebuilt once?
Besides the reset button, the motor is missing its on/off toggle switch. I believe the GW or GWI series was the only model to have that feature.
Check out Delphi forums Dewalt radial arm saw group. It is the same bunch as the Yahoo DeWalt group, and besides OWWM (already saw your pictures there), the best chance to find one (I know of one other person looking).