That sounds like a nightmare waiting to happen. Imagine they have the "wrong" old-dog adopted by an innocent family, and something bad happens afterwards? Who is the family going to blame exactly? More importantly, who are you going to call out if that were to happen? Be honest.
Where do you think "bad old dogs" at the animal shelter come from? It's also easier to predict an older dog's behavior than a puppy's eventual behavior.
Maybe instead this should be left to the professionals. There's some honesty.
It was adorable.