Curious about this as well.
Does the NL mailer code / link guarantee that you dont get the "you can proceed with the application but you dont get the bonus" notice?
With a NLL offer, you won't get the popup saying that you're not eligible for this offer due to having the card before, it bypasses that. However, you may encounter the other infamous popup saying you may not be eligible for the welcome bonus due to your history with AMEX, meaning AMEX believes you're a churner and gamed their previous offers so they won't be extending you this one.