Kohler makes Black fixtures,and they are a bitch to keep clean. Every spot shows up on real dark anythings. Black is also a High Fashion Color, more $$$ than regular colors. If you do go the re-finish route, ask at several plumbing supply houses who they use. Not unusual for fixtures to be chipped during shipping so suppliers use these refinishers regularly. The same name will keep popping up, use that guy.
If you sledge the old tub, 3 big pieces ought to do it. Smash the side near the top of the apron first, then take the apron itself.Next is the tub floor. Watch your backswing. Wear a facesheild as the porcelain will splinter into razor sharp pieces.