Hmmm. Not so sure.

Merrion-Webster online:

Theories about the origin of copacetic abound, but the facts about the word’s history are scant: it appears to have arisen in African-American slang in the southern U.S., possibly as early as the 1880s, with earliest known evidence of it in print dating only to 1919.

Dictionary.com

An Americanism first recorded in 1915–20; of obscure origin;

Wiktionary

Stephen Goranson says "there is good reason to think that Irving Bacheller invented the word [with spelling "copasetic"] for a fictional character with a private vocabulary in his best-selling and later-serialized 1919 book about Abraham Lincoln in Illinois, A Man for the Ages, and its currency increased by use in the 1920 song "At the New Jump Steady Ball".[1] Alternatively, it has been speculated that it may have originated among African Americans in the Southern US in the late 19th or early 20th century, perhaps specifically in the jargon of Bill "Bojangles" Robinson, who certainly helped popularize it in any case.