The 8 scenarios do feature specific forces, as they are historically based.
Forces include; Reds, Whites, Bukharans, British, & others. Up to around 80 figures a side, mostly foot, but up to 3 cavalry units. Various proportionate supporting elements; HMGs, Field Guns, Armoured cars, even the occasional armoured train or aircraft. Pretty much the kind of thing required for any StEA game.
Unit types vary alot, are too numerous to list and it would be unfair to the author to do so. I doubt many of us (except Ignatieff & Lord Raglan?) would have all the exact options required in the book.
However, I've played most of the scenarios, but substituting available forces. I have Chinese Warlord, Chinese Bandit and Turkish armies (Unpainted Reds to come at some point...), my regular opponent British/Empire and Whites. My Chinese stand in for Reds and other forces all the time.
I hope that helps a bit.
Gratuitous BoB pic: