Yes, that can work. The issue here is that "le côte avant" really is "the front side". The French also use the noun "l'avant" as "the front" of something, e.g., L'avant de sa voiture a touché l'arrière du bus. http://www.wordreference.com/fren/avant Remember that a lot of Duolingo's exercises are just that, exercises put together to expose learners to how words are used and not to portray it as the only way the idea would be expressed.
It's perfectly fine in French and fine in English. It may be a choking point for some that "front" means one thing and "side" means something else, i.e., since it is the "side", how could it possibly be the front? N'est-ce pas ? When we apply absolutes to such discussions, we may forget to take on a perspective that considers there are other contexts which are not just possible, but quite natural, even if we don't use it ourselves. In English, we would indeed just say "front" without saying "side" but it is certainly not wrong to include it.