Many Clone High episodes have jokes that have to do with history, but there are also innacuraties.
The diner the clones frequently go to is called The Grassy Knoll, a reference to the JFK assassination conspiracy theory about a second shooter, dubbed "The Man on the Grassy Knoll". Other references seen are the flag at The Grassy Knoll being permanently at half mast and the car on the roof of the diner containing the original JFK's body leaning over the edge. There are pictures of assassinations hanging on the walls of the restaurant, such as the famous Currier and Ives print of the Lincoln assassination (though this version is in color and considerably more graphic than the original print).
The genetic ancestors of all of the five main clones died of similarly irregular causes: three assassinations (Ghandi in 1948 , Lincoln in 1865 and JFK in 1963), one execution (Joan)and one suicide (famous Cleopatra's suicide with a snake) .
Abe mentioned that the clone of Napoleon is so annoying because of "some kind of complex". Gandhi has told Catherine the Great to "get off her high horse".
Like their clone-parents
Many clones are partly or fully like their original clone-parents. Cleo is spoiled, mean and narsisstic like Cleopatra vii , Van Ghog is a good painter like his clone-father, Joan has religious issues, Elvis twins are liking peanut butter and jelly sandwich like original Elvis, G.W.Carver is also genius scientist interesed in peanuts(he is better than his clone-father since he made a talking peanut).
Cleopatra was greko-macedonian not egyptian, Napoleon was not so short for that time ( 5'6" (1.68 m) tall ) , Paul Revere didnt make that famous night ride alone, Marie Antoinette didnt have a french accent since she was from Austria and it's not certain that Helen of Troy was real.