Maybe, but I doubt that Apple would want their employees using MS products when they have their own in-house software available (Pages, Numbers, etc.). I know you can save files as a Word doc in Pages, though I'm not sure if it can specifically do .docx though.
I swear some of you guys crack me up. The reason MS is doing this is because they'll be coming out with Win8 tablets and they don't want employees supporting the competition. Do you honestly thing there are folks using Office in Cupertino? I'll give ya a hint. There aren't.