Hero of Legend
Member
https://www.nintendo.co.uk/amiibo-/amiibo-details/Link-Ocarina-of-Time--1136389.html (EXAMPLE LINK, read the paragraph to see that it isn't guaranteed)
Initially found on Reddit showing the Archer Link amiibo but with no link (ahem) and just a blurry image, I went to check myself and, sure enough, if you look at any amiibo and look at the "Discover more amiibo" section, it shows you 4 random amiibo, and the BotW ones (so far I've seen the Rider one shown) will show "04/03'2017" as the person on Reddit found. Just seeing them from the main amiibo page or the BotW amiibo pages themselves will only show "2017".
Now the obvious next question is, does this potentially also leak the game's date itself, and most of all, the NX's launch date if BotW is going to be a launch title as was Twilight Princess on Wii? That is not certain. I think it's likely that the amiibo could just launch independently of the game and NX, but a simultaneous launch would be a great idea though.