Yes, it would be considered very poor form to do so.
The kennel name denotes who bred the dog, and if the pup didn't come from that specific kennel it is considered untruthful and unethical to use that kennel name, as it implies the pup did come from that kennel.
This is a pretty common question and mistake often made as people often consider a kennel name like a last name/surname for people, but it's not intended to be used that way.
If you like the vom Wigglebutt type format for a registered name, and your pup's breeder doesn't have a kennel name that he/she wants the pup registered with, you can always make up one using your last name, favorite place, street you live on, city you grew up in, whatever you want so long as it isn't an existing kennel name already in use.
