Yes, you're thinking of the right screenshot. Some of us suspect the entire pic's a set-up, since we doubt a barbarian unit would be that ethnically/regionally/culturally specific, as the barbarian units have always been pretty vague in terms of ethnic/cultural variation. Since the tomahawk weapon, as well as the mohawk hairstyle the unit has, was only prominent in the eastern US, we then conclude perhaps its hinting at an eastern NA civ - note that this can mean any NA group from the Alongquins way up in Canada, to various Ohio and Missisippi river valley folks like the Shawnee, to all the way in the south with the Seminole and Cherokee, so I'd hardly say the Iroqouis would cover that.
Whether you buy that line of argument is another matter altogheter.