Yes, they would come out of it, but that idea worked for early firearms! And if you want to do the touch hole, wear heavy gloves! You'd get burned by the flames.
The propellant gasses would go out, but if it's a tiny hole big enough for a match, not much would leave. It keeps you from having too big of a fuel/air mix.
PS: If you do the touch hole, it could be dangerous! A powerful flame would come out. You should take a dowel or something and attach the match to it, so you can stay a few feet away and behind the hole (the match doesn't need to go through the hole, it will ignite gas outside and that would lite up the rest)