I say no, without papers you have no way to know what the dogs lineage is like. What if grandparents and parents are train wrecks and all the stars aligned for this one specific dog just by luck. You need to consider not just phenotype, but also genotype. The dog is not just passing on in his genes what you see in that dog. There is so much more too it than that. He is passing on alot of stuff that isn't physically expressed in his physical appearence. Also I would never breed to a dog without several generations of health testing behind it. So many things like hips, elbows, knees, etc are polygenic genes. There is no way to rule them out with a DNA test like PRA or CMR. He might have good hips, but his mother, her mother, and 1/2 her siblings have dysplasia, your litter from this stud is more than likely going to possess some of the genes for dysplastic hips.
There are just too many ifs. Plus no dog ever produced by the dog could be registered. There are many quality studs out there that are registered, have generations of health testing as well as being conformationally pleasing. IMO there is no reason to breed an unregistered dog.
