Kind of a quick question about my neighbors horse.

My neighbor got this paint/paso fino for free, the lady gave it to her saying it had similar problems to my horse, rearing and bucking and stuff, had a vet check and everything came u clean. My neighbor isn't the brightest in the bunch, but she's now boarding it right up the street and I know she was afraid to get on. (She'd rather have other people do the work for her, I guess ) I went with her to check the horse out, and told her if everything was okay I'd get up on the horse for a minute. They have a round pen there (I'm thinking of moving my horse there) and we put him in the round pen, and I worked him for a little bit...he bucked and kicked at first, but I think he was just full of energy, he's just in a smaller paddock. He did very well and was soon following me around the roundpen and I could do anything to him. So, I tied a lead rope to his halter and got on, and he behaved VERY well. I realize this is the first day riding him, but I was somewhat impressed. He is, however really responsive to any of the aids given to him..especially with his head (turning, halting, etc) and if you asked him to go, he went! He didn't really respond to the leg to move over...if you put your leg on his side he went faster.

Neighbor says the lady says that he has been ridden in a hackamore, but I don't know what kind. I wonder if I SHOULD bit him, or if I should put a side pull on him, or my own horses hackamore. I guess we could use trial and error, but I just needed an opinion. I'm hoping maybe that lady just didn't have a clue and he turns out really nice, he was supposed to be a kid's horse but I can't see a kid riding him.