A military technology should be coded 'present' if there is concrete evidence that it was used in warfare (e.g. metal in armor or weapons, spears used in warfare and not only in hunting, etc) and 'inferred present' if there is evidence that the polity used the technology (e.g. for hunting, as an ornamental or ceremonial item, in jewelry), but no concrete evidence that the metal was specifically used in warfare (explain in comment).