I was given a Nicca rangefinder camera with a beautiful Nikkor 5cm 1.4 screw mount lens in addition to a Canon 135mm f3.5 screw mount with viewfinders too. Very nice build quality, much like a Leica M3. My question is, how do I align the lens to mount properly with the camera body to engage the roller for frame lines? There's a groove cut into the brass threads on the lens mount, i'm thinking maybe use this as a reference.