Did all Six BBL Superbirds come with Cart Iron Intake Manifolds?

[RSI700VIPER]

I've seen several Six BBL Superbirds at shows who's owners claimed their car was original, but some had aluminum intakes.  I though Chrysler switch to cast iron manifolds very early in the 70 production run which would suggest no Superbirds came with them from the factory.     

[cudavic]

My friends bird had an aluminum Edlebrock six pack manifold on it and the car was all original.

[Golden-Arm]

a discussion about these manifolds https://board.moparts.org/ubbthreads/ubbthreads.php/topics/2728452/when-did-chrysler-switch-to-cast-iron-six-pack-manifolds.html