I'd be really interested to know for sure whether this green tint was present in the theatrical release or not. The low-quality screener DVD that the studio put out for Oscar consideration definitely had no green tint to it; actually the colours were pretty poor with blues looking purple etc. but there definitely was no hint of green.
I dunno about everyone else but I'm gonna be paying serious attention to the colours when watching Desolation Of Smaug in the theatre.