The NDS cup is always right hand threaded to my knowledge.
http://sheldonbrown.com/harris/botto...ets.html#sizes

It sounds like your cups are swapped. That would make it a pain to adjust with the chain rings in place.
OTOH, I've heard of people using adjustable cups on both sides to fine tune a chain line. I imagine that is getting harder to do, considering the scarcity/expense of parts.