Well Thanks Sid for the photos, that brought the control system into focus.
I remember now, the collective control rod goes inside the mast which actuates the spider arrangement on top to alter pitch collectively.
So I would guess the story is referring to the control rod on the port side of transmission connected to the collective lever.
So perhaps is possible to get outside and manipulate it, the Hiller 12E being a three seater.
The unaswered question is what happened to the bolt nut and split pin.
BH