HR, I see you're quite good at ferreting stuff out online. I don't know if Smithsonian puts their articles online, but you might check and see if you can raise the last issue of Smithsonian Magazine wherein there is an article on this topic. It tells of some finagleing that the above receipt might refer to. Apparently our boy general got the horse declared contraband of war after Grant wanted it returned (even though it was grabbed after hostilities ceased) and then proceeded to purchase it as condemned stock (and thought he could get $10,000 for it!?!). Looks like the receipt you posted just might be evidence of just that sort of scam. I mean why would a man like GAC be buying a $13 condemned cavalry horse, really?
General of the Army (Medicine Man/Chief))