Ladder sight question

[Coonan357]

Not a huge issue in the grand scheme of things. But this is puzzling me. I've tried to research the answer but I'm coming up empty.
What is the hole for? It is bored through and it is not threaded. This is a Smith Enterprises ladder sight.

Thanks in advance.

 

[Coonan357]

From the main authority at Smith Enterprises, "that's just to hold it in the fixture. We don't need that anymore."

And there you have it.