Duels? No clue, honestly. They definitey happened, but their frequency could definitely be overstated. As for meeting at noon? I think it sounds like the most reasonable time and would’ve been common if duels were common. This is pure, complete speculation on my part, so don’t repeat it without doing your own research, but I think the existing facts support my conclusion:

• Home clocks at the time were only seen among rich folks, often as a status symbol.
• Even if you did have one of these, they often lost quite a few minutes per day.
• Towns often had a clock for the church.
• This clock would’ve been more accurate than a home clock.
• This clock often rang at noon.
• Noon is (approximately) pretty easily verifiable by the position of the Sun being the highest in the sky.
• Noon means that neither party should have an advantage based on where the Sun is facing if you line up east–west.
• Noon is around a time most people are most likely to be the most awake.