Jochen,
I'm hoping, as I'm sure you are, that
Curtis or someone who's handled thousands of these will chime in.
But to address your concerns... Could the hair have been touched up? Yes, certainly. The reason I don't think it has been is because higher points of the obv have natural wear and no evidence of tooling. Tooling would be necessary in order to recover detail on the
bust, but it is questionable how much wear the hair closer to the
field would have experienced, being so much lower than the rest of the
bust.
I can imagine that the
weapons on the
reverse are sort of in a protected zone formed by the curule chair and the
legend, both of which are probably significantly higher than the
shield and spears, which seem fairly low relief. This coin seems to be very high relief, so that could account for the unnaturally clear hair and
weapons.
At least that seems logical to me, but I'm stepping aside now for experts on these bronzes to weigh in. I hesitated offering an opinion, but so it goes.
Mark