Thanks everyone. I just phoned them with the part number and they said I'd have it in 7 to 10 days. Painless! And now that I look closer I do find a "missing or broken parts" section on the site.
i had this several times here with different sets in NL, just filled out the DS order form and added the missing/broken parts with their part numbers and crossed the mark in the field on the form missing or defect. 
Within a week i received the replacement parts without any cost. It should work the same way in the US?
To my knowledge you can't order DS online in the US, so I don't think this is possible. I could be wrong though.
Be really specific about the part - use the number for it.  The only time I had a broken part I made the mistake of using words when I told them what was wrong.  It seemed to me that there would be no room for error as it was a simple exact description , but they sent me the wrong thing. But they did send it quickly!   
 
We're a digital culture now, it's all about the numbers!
This same thing happened with my schooner, exact same break in same place... they sent a whole new hull/deck piece... I always call for broken/damaged pieces...  but it is always a little frustrating to look at the incomplete/broken set for 2-4 weeks while the part comes... slowly  
Must be some sort of misalignment at the factory, breaking the same bit on multiple pieces. I hope they've solved it. 
Finally: THIS SET IS SO DAMN BEAUTIFUL. I LOVE IT. 
The stickers freak me out though, as usual. So hard to get right. I wish they were just printed on.