This clubhead is made from two separate pieces. Removing the screw in the sole allows for detaching the hosel and shaft from the head proper.  The hosel can be positioned to make the club a normal right-handed putter or reversed to make it a backwards left-handed putter. Yes, backwards putters date back to the wood shaft era. 

Herbert D. Challis and Samuel J. Williamson received a U.S. utility patent (No. 1,454,267) dated May 8, 1923, that covered this club. Challis also received a U.S. design patent (No. 63,284) dated November 20, 1923, for this club.

The design patent covered the external design\shape of the clubhead. The utility patent described how the head could be removed from the shaft so that the golfer could easily install a new head if the original one became damaged: "A set screw with head or washer rabbeted into the head of the club from beneath bolts [the neck] to [the] head, binding [the] follower block in its tapered recess."

This club is in excellent shape. The 35" shaft is original and the leather wrap grip is an old replacement. 

For more info, see TCA2 v2 p485