^ Well, female top and male bottom is what the swap would end up being.
OK, scientifically speaking, the bottom half is where the "genitalia" of the swap character would be. The fact is swapping between a female swaplander and a male swaplander would only result in the top portion that was female becoming a male "biologically" (though, in reality all they did was borrow someone else's physiology) and the top portion that was male would become female. Hermaphroditism occurs either when a being/creature has both reproductive organs (i.e. genitalia) or shift into the opposite sex for reproductive reasons. This example is closer to transsexualism but not even because, essentially, they are simply borrowing the other character's bottom half!
TLR, a male and female swaplander exchange would not be a hermaphrodite but wouldn't be transsexual either. They just swap.