I'm no anthropologist, but I think there's a big difference in the learning curve from beating out native copper, to mixing it with tin to form the harder alloy brass, to smelting iron ore, and finally to discovering that adding charcoal to iron produces the harder-yet steel. There are certainly many many centuries separating the discovery of these processes, so I'd be careful to tie one of these metallurgical ages to the timeline of the Cimmerians. Otherwise, neat essay Kane.
If Conan's grandfather was not the first man to bring metal working to his tribe, then he was most likely one of the first to bring iron/steel working to the tribe.
And I also found this quote on the internet, make of it what you may, I don't quite agree with it. I did like Ironhand's definitions in the first post in this thread.
"Now man can be opposed to himself in a twofold manner: either as a savage, when his feelings rule over his principles; or as a barbarian, when his principles destroy his feelings. The savage despises art, and acknowledges nature as his despotic ruler; the barbarian laughs at nature, and dishonours it, but he often proceeds in a more contemptible way than the savage, to be the slave of his senses. The cultivated man makes of nature his friend, and honours its friendship, while only bridling its caprice."