I only quoted one line from D582's post to avoid cluttering the thread, but if you read it just a few posts up you can see they included a link that shows that in the most recent archived version of the page (Feb 22, 2024) AC told customers "Looking for an aisle or window seat? You can always select your seat free of charge at check-in. But if you’d rather not wait, you can pick your seat in advance, free or for a fee". (Bold in original.)

If you google "You can always select your seat free of charge at check-in", you can see it's also present in google's most recent cache of the page.