Huck's knowledge of King's and Dukes is a wonderful satire on royal life and pretense. It's not completely accurate, but many of the inferences he makes come close enough to historical truth to be entertaining. When asked what kings do, Huck echoes some of Twain's satire about politics. Huck says "They just set around----except when there's a war, then they go to war." In an obvious allusion to the French Revolution, Huck says, "When things is dull, the fuss with the parlyment and if everybody don't go just so he whacks their heads off." Huck also alludes the the riches kings and excesses of inherited wealth, "Why, they get a thousand dollars a month if they want it; they can have just as much as they want." Plus, Huck says, they also "hang around the harem" and have a lot of wives--an obvious crack at royal infidelity. However, his knowledge of kings and dukes will soon be tested when he and Jim run into a pair of con artists named the king and duke.
It's not accurate because he is uneducated and cant read so the books don't give him information, so he just makes everything up.
Huck information is very accurate .. He gets his information from the king and duke themseleves.