Similar with HA Card benefit when flying HA
While this was not Alaska Credit Card, I had a similar problem with Hawaiian Card, as I was not a member class when I purchased the ticket (used different credit card), but was a valid holder by the time I flew. The benefit clearly indicated I had to use the credit card to purchasing the ticket for the benefit to apply.
Now that HA and AS are being integrated, am not sure how this benefit will be applied.
Jiburi