I noticed that in the Age of Empires wiki, it lists that the US gets a unique Imperial Age skin for the Hussars, making it resemble a Union cavalryman during the Civil War and Indian Wars, wearing a kepi.
However, when I reach Imperial Age and upgrade the US Hussars to their Imperial Guard level, I keep the generic Industrial/Imperial Age skin. Is this a bug, or a real effect that should be happening? I think the unit looks pretty cool and is another thing that makes the US interesting, plus helps the roleplay in Civil War or Indian War scenarios.