I have one that does not have the piece of sheet metal in between the top & bottom of the frame. I think it is an earlier version. B.K. Brooks (writes for Knife World) told me that people were cutting their fingers when closing the knife, so the sheet metal was added. Mine is about the simplest folding knife possible; a blade, wire frame & pin. George Schrade was granted the patent on the Wire Jack, one of many knife patents he had. I am told he was trying to make the simplest and least expensive knife possible, and the Wire Jack was the result.
I think they are pretty clever.

Dale