I would be a little bit surprised if campy threaded the cranks before they were anodized, since anodizing can change the surface of the threads by growing a hard oxide layer.
My suspicion is that if the threads are black, then its an elementary after-market anodizing effort. A better after-market effort would mask the threads with masking compound before anodizing, so that they remained silver.
Similarly, the chainring teeth will be silver if they were anodized at the factory. At least that's how my black sugino maxy rings rings came way back in 1977. I think the same thing goes for the drillium holes in the super mighty chainrings.
An original crankset should be all black with silver threads and chainring teeth which have lost their anodization during the drilling/tapping/milling process, i believe.
- Don Gillies
San Diego, CA