If it has working lights there will be center-rail pickups on the trucks, and probably some on/off switches. Any remote couplers will have thick shafts (for the solenoids) and 2 wires going to each coupler, of course. You can probably see some wires through the windows if class lights are present.
A TMCC board in the dummy, or a tether to a powered, TMCC loco, would be required to have remote couplers - or remote anything.
Atlas's website may have old catalogues as pdf's or the like.