besides the physical. there's always the appliance of those body parts that can not be exchanged. unless someone twisted thinks of sewing the head of someone alive onto the posterior of another live organism. but even then technically its still the way the organs are applied, and the physical look.

what of the metaphysical properties of said "Ass" and "Face"?

face: has all 5 senses on it.

ass: gives off waste products such as excrement.

Would such metaphysical states be transferred over to the opposite position of the body.

might be possible. if you lower room temperature. and commence a surgery to swap both body portions.

Wouldn't that be like simply flipping upside down? I love how on topic this is.

no. . because your legs would be closer to your head as your ass is closer to your shoulders.