Yes, they're best frozen raw just after they've been formed into balls or patties. To do this line a baking sheet with baking paper. Lay the falafel out on the sheet with space between each then freeze. Once they're frozen, remove and place in an airtight container which can be returned to the freezer. Doing it this way ensures the falafel don't stick together from being tossed into a container on top of each other.