What is your car's rarest option?

Not an a-body but my long gone 64 Dodge Polara 500 with a 361 big block and a 4 speed manual had a factory tachometer in the center console. I have never seen another one with the factory tach.
My 1969 Dodge Polara 500 Convertible has a factory 383 four barrel that is rated at 5 hp less than the Road Runner engine because of a slightly different camshaft, everything else is the same as the HP 383. Oh, and it has factory air conditioning.