You can do it in a few ways actually, again, all depending on your setup. If you have spawners that are not enabled at the start of the level, but activated as you progress, you can get property/enabled and store it as a bool which you can compare on load and do what you need (enable it/disable it).
If all the enemies are spawned at atart, you can simply make a sort of a local counter variable in each spawner. Spawner checks the "counter" int variable, if it's zero, it spawns an enemy and adds 1 to counter variable. When you savw the game, you save the counter variable too. On load, fsm checks the counter variable, sees that it is 1, and spawns nothing amymore.