Bjorn,
If you turn down the saturation knob on a colorized film broadcast, you would
be looking at the original b&w "more or less"--but you should expect a bit
more stress on the "less."  It is not quite the same as having an untouched
b&w print broadcast for reception.  What's been done to it to colorize the
thing ends up compromising the film's gray scale (range of blacks to whites,
in effect) and even its sharpness.  You can't retrieve these things by turning
down the color and fiddling with other knobs for sharpness, contrast, etc.,
in my experience.
Jeff Clark