If he were a Paint, the OP would know, since he'd be registered. Paint is a breed. Obviously he's a pinto of some kind, since he's not registered as a Paint.
As I've said before, Paint is a breed of horse. Pinto is a colour description and can be anything or a description of a colour in several other breeds. For example, many Mini Horses are considered pinto, which means they are possibly black and white, bay and white, white and grey, frame etc. But they are NOT Paints - they are Miniatures.