These guys are correct, you'll be shooting in Match Rifle class, not Service Rifle, but that's neither here nor there, because the US Service Rifles are head and shoulders above the FAL as far as sights go anyway, so you're at a loss even against a Garand. Compete against a guy with a match prepped AR Service Rifle and you're way outclassed.
But.
The game is an individual sport, and you shouldn't decide to not go becuase you'll be outclassed. Instead, you should go so you can learn how to shoot your FAL better. Forget the competing, just go for the fun and learning.
BTW, if you have a brake on the rifle you won't be welcome. Otherwise, you'll be WELL received.