I think the S+ are in/out & ground.
Each time a break in the light is detected a coin has passed.
One of the cheating methods was to shine a very bright light into the slot either through the coin in or coin out.
The latter was less obvious to casino security. If you could blind the optic the hopper would continue to spit out coin until which point you either got a time out (coin-tilt) or the coins have been counted.
So you could turn a single cherry 2 coin win into an easy 40 coin win. Run the light for 20secs - turn it off for a moment, before you get a hopper error and turn it back on before it finishes paying, repeat.
The optics are probably physically the same in the S2000 but that other board probably introduces other security features like oscillation of the optics.
This way a very bright light would not have the oscillating pulse that the emitter is expecting and it would go into a coin-tilt or a security alert immediately instead of continually running and spitting more coins out. I am just speculating here.
SO... if you want to use the S2000 optic in the S+ your going to need to connect it someplace other than the 5 wire board. Which likely means taking it apart and soldering in all new wires etc. Probably more trouble than just ordering in a dozen S+ hopper optics.