Technically yes, but it feels very different to an open office with 50 people in it. <=10 is small enough that everyone is able to respect each others' privacy, noise, etc while still enjoying some of the benefits of an open office such as turn-your-chair-around collaboration. I think we need a new term for when <=10 people are in an open office. It just isn't the same as what is usually referred to when someone says "open office".