Well, I did just run a test by disconnecting my BE camera, and cutting module actually works without it! Although I have only tested the Pen for now, but it actually works.
Therefore you can rest assured that the Cutting Module DOES work without BE camera, although positioning won’t be that precise without it.
But as of now, if you want to install one, to calibrate the BE camera it seems that you require the Laser Upgrade Kit or Laser Edition.