When Grandpa Duck reappeared in the Duck Family Tree drawn by Giovan Battsita Carpi (first printed in 1994), he and Grandma Duck's husband (as he appeared in The Good Old Daze from 1964) were shown on different portraits. Grandma Duck's husband was here called "Donald's grandpa", while Grandpa Duck from the 1955 cartoon was called "Donald's great-grandpa", implying that he is in fact one generation older than Humperdink. This information is, however, not given in the original cartoon in which Grandpa appeared.
Theatrical release poster of No Hunting.
Grandpa Duck in "Your Host, Donald Duck".
Grandpa Duck, as he appeared in the Donald Duck Family Tree Pin Set (2000s).