The only results I found from people using "Rogue" and "Duel" together in past posts are people who spelled "Dual" wrong when they were talking about their dual wielding rogues. Did you maybe confuse those two too?
I also checked the wiki history after that and even in 2016 the Duel page had only Cleric and Warrior as possible classes, so Duel was never an option for Rogues. Not even in the very early stages of the game.
I don't know where you found that information, but it's completely wrong. Besides, Duel wouldn't even be that good of a skill for Rogues.