I would definitely try to warranty. I work in a shop and have seen several models come back with sidewall missing (more specifically the Kung Fujas and the Extreme). I was amazed the first time I saw it, but I have seen several skis come back missing quite a bit of sidewall. Take them back to the shop you purchased them at. They should be able to take care of it for you. If they don't...I would seriously question buying another pair of K2's.
My experience is the past is that K2 has an excellent warranty dept. The only problem you could run into now is availability. K2 has nothing available at the moment. Might have to wait til next year to receive anything back, but the sooner you get them in, the better your chances.