Went right over my head like one of Stewart's bullets.
In the movie, The Man Who Shot Liberty Valance, there's a similar error in the script. Pompey is taking classes from Ransom Stoddard (Stewart's character.)
I'm quoting from memory, so may be slightly off:
Pompey: "It was writ by Mr. Thomas Jefferson of Virginia."
Stoddard: "Written, Pompey."
Pompey: "And it was called the Declaration of Independence."
Stoddard: "The Constitution."
Pompey: "And it goes like this: We hold these truths to be self-evident..."
It's one of those little errors in a movie that shows up on movie trivia sites sometimes. When I heard Rush make the error, the first thing I thought of was the movie.