Since you said "he" I assume the new fella is a gelding. Ok, you can't breed him so what's the point paying extra money for a 'registered" animal when you can't breed him? The only thing that would matter is if you want to show in breed specific shows. Being registered just proves that the horse is a "purebred" of a certain bred.
My gelding is an appendix QH. Why should I register him?? Bragging rights? Is he going to jog smoother if he is registered? Your bill of sale with CYA in case of theft. There should be a vet record, a coggins, a bill of sale. Never hurts to jot the sellers licence tag down on the paperwork either.
Up here in the New England area, papers seem to be very important. :roll: In the mid Atlantic, nobody could care less. It was appearance and performance that mattered. Some people set a lot of importance in registration papers .... and then charge you a good bit more money because he is registered. WHY? What's the point in a gelding?
What do you expect out of this horse?