I just checked and I also have access to skirmishers in Amorica so that appears to be correct.
One thing I have noticed that is definitely some kind of a bug, at least in my current play through, is that I can't recruit chariots anywhere. The chariots I currently have are my original ones from the very start. I have wheel makers in the appropriate regions & provinces but the icon to build chariots does not appear.
On a separate note, does anyone know how to abandon a province?