Yes that was my guess as well. The breastplate arrangement with the pommel horn just seems weird to me as a horse person. It would put stress on areas of the horse that I would consider detrimental, especially given the speed and distances these horses were expected to travel. Not to say that isn't the way it really was and then later changed/evolved once they realized that maybe there was a better way
I've been looking at lots of saddles and stuff and it is very hard to figure out where the breastplate was actually attached as the shabrak is usually covering that area. It would have had to be attacked either to the saddlebelt, or very high up on the base of the saddle. As it looks there seems to have been not much stress on that breastplate, the pistol holsters are attacked to it, and then a bedroll tied across, across which was then fitted the shabrak. I guess that arrangement was a very ancient one which was changed under the later military but it is a rather big mystery what exactly is under the shabrak...