'50 Model 7 cam sprocket pin?

Hi everybody,

here is my trouble, I am getting ready to reassemble my '50 model 7 & see that the cam sprocket has a "drive pin" on the back, and it is nearly cut off (see pics), the pin seems to be pressed in & I am sure I could remove it, but does anyone have dimensions of what it should be? Does anyone have a new, or used sprocket for sale? Original part number: D12/79 (not D12/790).