Just for a point of reference SN 313625 (4" Nickel) has no logo and has the walnut stocks with gold medallions. No numbers found on the inside of the stocks, but with the perfect fit and wear, I am positive they are original.

Mine has not been lettered but my notes have 9/1919 as when the heat treatment of the cylinders started with SN 316648 - but, of course, that range of SN's may have shipped much later that that.

Rick