MD900,
The requirement is 3 hours of night training to have a private pilot's certificate. It is not optional, not a special rating/checkride and not model specific.
Better training, and less hassle, I think.
61.109:
2) Except as provided in Sec. 61.110 of this part, 3 hours of night flight training in a helicopter that includes--
(i) One cross-country flight of over 50 nautical miles total distance; and
(ii) 10 takeoffs and 10 landings to a full stop (with each landing involving a flight in the traffic pattern) at an airport.
Of course, in a Robbie, can you get 50 miles in 3 hours?? ;-)