Deliberate mistake: Conjoined twins Bette and Dot have freckles and moles on their faces and necks in the exact same places.
Suggested correction: Not technically a mistake; unlike regular twins, conjoined twins are always identical in appearance, contrary to what movies/TV suggest. This could easily include mole patterns.
I looked up "conjoined twins" on Google images, and there are numerous photos of conjoined twins having freckles and moles in different spots. Notably on the Hensel twins, Brittany has a mole on her chin, but Abby does not. This disproves your suggestion that conjoined twins are always identical in appearance and could have identical mole patterns.