What do you know about this PadLock?

[OutBack Duo]

I found this during the Chisholm Trail Hunt in Caldwell, KS. I know it can't be too old because the key hole is in the bottom but I have never seen a lock with a square shank on it.

 

[OutBack Duo]

I found a picture of one online http://www.antiquesnavigator.com/d-139322/antique-brass-safe-padlock-in-good-condition-no-key.html