Yeah, I kind of guessed that. However, I can see how it would be funny in Blazing Saddles, if it was a reference to another movie. If not, it's just a line that could be funny because of accents or inflections of the voice. While certainly there are quotable lines like this (Monty Python has several, the “I’m not dead” line being a prime example, even though it’s usually misquoted), I'd never found this one particularly amusing.