@ddljohn-- I have not seen black licorice candies that are sour. There are other flavors that are sour like green apple, strawberry, cherry and even flavors like mango, watermelon, lime and blueberry. You are right that sour apple is the most common flavor, it's also my favorite.
I usually buy the laces because once I start eating sour licorice, I can't stop. I tend to eat less of the laces because they are very thin and long like shoelaces so it takes longer to eat them.
The best part about licorice candies is that they are usually low in fat and calories, so they make a great snack.