I saw a new 32-minute restoration of this film (courtesy of the Chaplin Keystone restoration project) and came away with the feeling that half an hour was too long; the film degenerates into endless repetitive scenes that the more mature comedy shorts of the 1920s would have trimmed drastically to greater effect. However, reading other users' comments, I get the impression that the material previously edited out of "The Knockout" was actually the early, plot-based part of the picture -- hardly an improvement!
There are some funny bits; chiefly those that are allowed to stand as one-off gags and not over-milked by repetition. Don't (as if this needed mentioning!) look for realism -- the film clearly features the pair of six-shooters with the largest number of consecutive charges in the world, for a start...
There is, incidentally, no knockout in this boxing match. Much other activity, though; including Minta Durfee as a girlfriend with a decided taste for fisticuffs, Charlie Chaplin in a long-shot cameo as the referee, and a brooding Mack Swain apparently having trouble with his moustaches.