Here is the part number 418853601
Someone at DPReview wrote that they spoke to Sony today about their order. I'm not 100% clear if it shipped today of is shipping in 7 days.
I just called (800.488.7669) and ordered a few. Note this is not the regular Sony Style phone number. I called parts and accessories. The person I spoke with said they were due in on the 15th. They are only about $2.50 each plus tax and shipping.....
Since it wasn't 100% clear if he had the right date, I went for fast shipping to see if the caps ship or have a chance of arriving before I leave on Friday (shipping was more expensive than the caps of course!).
I will keep you posted on shipping status.