Or one could substitute some sort of small bead, if you could find one approx. the right size...
but I still haven't seen one yet that got even the basic shape right. Which is funny when you look at them and see that they were made with fairly simple shapes.
I suppose the reason is that any good model would have to have a lot of parts to model the upper half, with its armor (solar?) panels and multiple rings.
The Paper pokes version does actually have "Bumps", btw.
Love the Cyberman design from "The Invasion" and "The Revenge of the Cybermen" myself. The clear plastic jaw just messed up the look of the "Earthshock" version. But I haven't seen much Cyberman stuff other than a few helmets.