Just out of curiousity, if there are no holes for speakers wouldn't there still need to be some sort of opening for a Siri microphone? Given that the iWatch (mockup or official) will likely have a small screen, Siri seems like it will play an integral part interacting with the watch.
That made me pause for a moment and think about whether I want to talk to my watch, and how society might look with others around me speaking into theirs, too.
I'm comfortable speaking into my phone and headsets (ear buds, etc.) and the social etiquette that helps us get along with each other while doing it. But I prefer my watch to be a silent partner. The more I think about it, the more strongly I believe that voice interaction with a wrist-top device would be a disruptive nuisance. Besides increasing the level of ambient chatter, it would give rise to a new set of arm motions ("wristies"!) as people try to isolate/enhance the conversation with their watch, especially in environments that are already noticeably noisy or quiet.
Will be interesting to see what scheme Apple actually comes out with for interacting with the device. If not Siri, then perhaps bluetooth or wifi connection to an app that offers all of the "knobs and buttons" necessary to set the device and customize its behavior.