No, I HIGHLY doubt its an abcess. He is not obviously lame. He goes lame after about 45 minutes on a trail (ridden or ponied) and its not like super lame but his stride is off. He doesn't go lame when I can ride him that long in the arena, but I want to make sure his bucking in the arena isn't lameness related. Either way, when he is limping, its not like he's in pain (no head bob, and really wants to trot, canter...).
Anyways I need to sell him, because I don't need 2 horses, so I want to make sure I don't sell somebody a 'riding horse' that isn't ridable :).