The series' running gag of Mr. Burns being unbelievably old gets an additional wrinkle here. Burns' age is usually stated to be 104, so he'd be born in 1893 for the purpose of this story. But the series also contains frequent clues that he's even older than he lets on. In this one he owns a stock from "Confederated Slave Holdings," suggesting that he was already in business before 1865 (the last year of American slavery).
When discussing the value of Mr. Burns' shares, Smithers claims to be born 25 years after the Stock Market Crash of 1929. This means that Smithers (for the purpose of this story) was born in 1954 and is 43 years old.
According to Bret Hart, he was originally cast as an angry wrestler but not as himself. Hart wanted to play himself but the producers refused. When the producers saw how many fans were waiting outside the studio to meet Hart, they realized how popular Hart was and decided to animate Hart as himself. But they did not have Hart redo his lines which is why he is not speaking in his normal voice.
Uriah's Heap is named after the Charles Dickens character Uriah Heep, a bad man who causes trouble for David Copperfield. Mr. Burns tells Uriah "shine on you crazy diamond," the title of a Pink Floyd song.