I've got an Illustrated London News
print of Herati cavalry at Kabul c.1879 - can't dig it out right now, but I seem to remember a big furry hat, something perhaps like a busby - so certainly an identifying uniform of some kind.
Best - Garen
P.S. - just remembered: the Maiwand Day blog
has an excellent Afghan uniform resource, including Herati infantry and cavalry (the calvary uniform is directly from the print I mentioned above).