I'm surprised no one responded. Are there not still folks playing this old epic?!
And, to answer my own question, beware of the international zones that are coded into games, meaning that a cheaper price might net a product that won't install. Thankfully, due to no answers, I started researching this issue. Turns out that used purchases might not be so good--though it all depends. I decided to buy the aacw from ageod; and, I'm learning so much that is just assumed by cw2!!!
Hope this helps someone in the future.