It's true. With an action replay hacker. On bob-omb battlefield, second star, face the mountain (Making sure pre-game you entered codes for sprint & moon jump) and speak to koopa the quick. Speak until ready steady... and you pick. Before picking, tap L+up and b. Then, it'll show koopa the quick then show you. Time correctly, only one second in you'll manage to reach the top.

PS. Theres no real advantage you get for doing it in one second, but hacking sure prolongs a games entertaining-ness when you've completed in 100%.