I would definitely stay away from any D800 but brand new with 0 actuations on it. Believe me $400-500 savings will not be something you feel good about if your camera is affected and you have to deal with Nikon.
As for model - I would go with 800E instead of 800. There are a lot of reports saying that moire doesn't really show up unless you are in fact taking photographs of very fine textile patterns. People are saying that birds, landscapes, portraits are all very good. If you are trying to save money - then in my mind that'd be the only factor for D800.