Interesting. I had wondered about the wings myself. It's too bad this neat piece of equipment had so few detail shots taken of it.
I know the photo you're thinking of regarding what looks to be simply a flatcar with a Cat blade affixed to it being pushed by the OLC #7. Elvin said they would often borrow the Sumpter Valley plow, so it's possible this was the later/newer version (although it's also possible that we are simply looking at an OLC scratch-built contraption). I wonder if the old plow was retired after commissioning of the new one? I seem to remember 1941 as the build date. If so that fits in with the massive upgrades both the SVRy and OLC were undertaking in the immediate pre-war years.