It appears German Pekins differ from American Pekins. German ones were bred to be upward-standing, and they generally weigh less than American Pekins which were bred from white ducks that were transported to the Americas.
Additionally, German Pekins are show birds or meat birds, and don't lay very many eggs per year. American Pekins lay far more eggs per year (over double the average German variant).
He doesn't have the posture, but he's got the face and the build. I know for sure that his father was an American Pekin, but I suspect his mother might have been a German. Unfortunately, she passed just before I got this phone, I have no pictures of her.