3930 seat bolt questions

[Light1867Ranch]

The rear bolt on a 3930 seat attachment has some special step machining on the shaft. My question regards the bottom 3/8" of the bolt.
There is a flat spot on it.
Does this flat spot have a particular orientation (direction) that it rest?
OR
Is the flat spot actually a "worn" area and should be round?

 

[Light1867Ranch]

just for clarification -
I am referring to the bottom of the bolt (inside of the hydraulic plate) .
I had to grind the top of it and break the fine threaded nut free -