Just a data point: I used the 50k link on 5/26 (apparently just before it went away), got the card yesterday - and I called and verified that I do indeed have the 50k offer tagged to my card. Plus, they sent me a card without a chip, so when I called to ask, he promptly sent me a chip card via FedEx and gave me 5k more miles for the inconvenience.
I had been having some heartburn due to the fact that that link did not state the offer details on the landing page, but I put my faith in you all and was not let down - many thanks!