Not to put too fine a point on it, but Bob Runge hadn't even been born by the years the K and the K
f were appearing in the barrel steel location.
127801 03 K barrel steel.jpg
103266 03.jpg
The Walter King WK in an oval begins appearing in the 131xxx range. Here is a Titanic Steel barrel gun in the 131xxx range with the K in the barrel steel location and the WK in an oval --
131783 03 K in barrel Steel Location.jpg
Here is a 1906 vintage Vulcan Steel gun in the 138xxx range that has the V in a circle barrel steel marking. It doesn't have the Walter King WK in an oval, but it does have a tiny K on the barrel lug.
138615 06 V in circle.jpg
By the 151xxx range we see the James Geary JG in an oval marking