yeah thats true, seen things like that before being done, should be careful on this day not to get "fooled" and thinking on it, if you see the pic there, if it were a real gynandromorph, maybe it is or maybe not, the abdomen might look different sizes on each side, slightly.
Not a butterfly, but this page shows a moth which has recently hatched at the natural History museum in London. It apparently even appears to have a line down the centre of it's body where male and female areas merge...