Yes, it can be done to acquire papers for the Puppy that's presently an Grownup, but the method could be much more elaborate and time-consuming than registering a Dog. Grownup puppies can be registered that has a kennel club or registry, even so the operator should provide documentation that proves https://www.openpr.com/news/4286965/how-to-get-papers-for-a-dog-the-complete-step-by-step-guide