Flash commander pre-flash question - D800

I have an old SB-26 that has wireless slave operation, and I planned on buying an SB-700. What I want to do is go full manual with all settings, and use commander mode to fire the SB-700 (in umbrella etc) and set the SB-26 to be an optical slave for hair/background light.

I'm reading the D800 manual, and it states that built-in popup flash must be raised so that it can emit monitor pre-flashes.

Does anyone know if the pre-flashes occur if the built-in is set to off, and the Group A (SB-700) is set to manual? I think the pre-flashes would trigger the SB-26 prematurely. I'm hoping the pre-flashes would serve no purpose if I'm not doing TTL on or off the camera.