Here's another find from the Indian War fort site that I don't know what it is. It looks like it could be a gun part to me.
Now that you say that, it reminds me of the window latches on my son's house that was built in the 1930's. He replaced the windows when he renovated the house so I can't provide pictures. The latches would push through both sides of the window sash into the frame to hold it in an open position. The flat end allowed the user to grasp and retract the latch when it was time to move the window again.It strikes me as possibly being either window latch or cabinet door hardware.