Whoops, sorry; forgot to answer that one.
The horse is of good quality, and battle-trained. The tack is unmarked, of moderate quality and decently cared for, but has seen hard use.
The horse is branded, with a symbol that isn't familiar to you. It also has a partially-healed bullet wound on its chest.
A horse like this would cost several thousand dollars to buy; what you can sell it for, and whether it's worth the risk, is an entirely separate matter.
It is possible to transport a horse on some ships, but it isn't cheap. Horses are a pain in the arse on a ship; big, fragile, messy, panic-prone and dangerous.