Here's that proof you wanted:
https://www.macrumors.com/2015/04/08/apple-watch-models-april-24-delivery/
Did you read the headline in the llnked article?
Do you know what the word "may" means?
Did you look at the date of the article and realize that this was speculation 2 days before the launch?
Did you read the first sentence of the article?
Do you know what this sentence means part means: "a 4/24-5/8 delivery estimate, which is up to a two week time frame after the Watch's April 24 launch."
Do you know that a range of 4/24 - 5/8 includes the date of 4/24?
Do you realize that availability of watches in Tanzania is also limited, even at launch?