I've read several reports that AppleWatch deliveries may very well happen before Friday. With Apple removing the April 24th date on the website, anything is possible. I don't think they will be so particular about the delivery date as they have been with previous product launches given all the changes that occurred with the launch of this product and the fact that it won't be available in the store anytime soon. I think early delivery to some might generate some goodwill in fact for Apple.
There is no logic to this if you compare to most product launches that only quote launch day as the delivery. I suppose anything is possible but highly unlikely. If it does happen I doubt it will be for the majority with some people also receiving after Friday in the first wave.