This gunmetal putter with a small flange is prominently marked "Harry Schopp Special" on the back of the blade.  Harry Schopp was the professional at South Grove in Indianapolis, Indiana between 1914 and 1928. This putter was made for Schopp by MacGregor.  While it does not bear any marks that identify Macgregor as the make of this club, this club is a MacGregor model 60 gunmetal putter as shown in their 1913, 1917, and 1920 catalogs, among others.

The 35" shaft and leather wrap grip are original, although half an inch of the grip has been removed from the butt end of the shaft, likely done by an owner who wanted to customize the grip for his or her personal use.  Even so, the grip is solid and tight. 

Condition as shown in the images.