I'd be a bit surprised if the smoke output isn't active by default. There'd be no reason to disable it and make another part to stock.
Just to put some closure on this one, I installed per the markings on John's board pictured above, and all went well. This is powering a single pullmor in an 8111 DT&I diesel - no heat issues at all on a light load. Interestingly, the smoke output appears to be functional, providing track voltage in F and R, and providing track voltage with a 50% duty cycle in neutral.
For whatever reason, Lionel chose to include a 6 pin cable with 5 wires installed - just not the right one! It has the correct black molex connector and fits the board perfectly. Unfortunately only ONE of the color coded wires was in the correct position to match up with normally accepted color coded functions (blue & yellow = Armature, green = field, etc.), and I didn't have a pin release tool that small, making a simple job of relocating the wires completely impossible, so I ended up soldering wires to the bottom side of the board. Not really necessary to match colors to function, but it sure helps the next guy!