Hello,
Plesae note that by redeeming a key for BFBC2 you would not get Vietnam access as Vietnam is an expansion pack and a separate code comes for it.
Only if you purchase the Digital Deluxe Edition through Origin store, you get Vietnam key along with BFBC2 base game.
Further, I want to share with you that Origin has a functionality through which you can activate Digital Deluxe Edition game through it, even if you have the standard version key.
I hope this information is helpful for you.
Regards,
Arya
