You mean the slotted screw that should be inside the oval slit or the clamp lever pin? From the way you highlighted the image it seems that you are referring to the pin lever which seems to be missing but instead it is only rusty. It's a typical defect of the FOLMER clamp pin lever which is in untreated iron. And it's also further confirmation that most of the Graflexe used in the OT were FOLMER Graflex.
I think he means the pin that holds the clamp lever? Maybe? If it is it's not a screw, it's a pin. Different versions of the graflex have different pins, so maybe that is what you mean?
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