Duo, you're thinking of the pre-order rewards. You can buy a gamecard or simply set up your subscription info to redeem them. However, those are not the veteran awards being discussed. Does veteran time begin counting when they charge you or when you subscribe...that's the important question here. I would be willing to bet that if you set up your subscription info you are g2g.
When you subscribe.
So if you sign up for 30 days, then you get the 30 day reward. If you sign up for 30 days, and play for 90 days (renewing your sub of course) then you get the 90 day reward. If you sign up for 90 days now, then you get the 90 day reward right away, and any subsequent rewards when they come out with them (assuming you continue to be subscribed and all that).