I tend to think that anyone who got the 4-24-5-8 shipping date will get their watch on Friday. It really doesn't make much sense, otherwise. Apple tends to give much more nebulous timeframes--"May," or "Four to six weeks." The dates tell me that they left some leeway for shipping delays, but if one watch (of a particular category) is in the country, they all should be.
Apple hires entire 747s to fly launch day products to the States, it's not like they called FedEx, who picked them up in China one by one. I'm sure they're all here already and fulfillment is what's taking time.
At least, I hope so...