Posted April 22, 2014
See this response by Raven01. So, I think for your situation, it implies that you can't add the unc version if you have the cen version.
http://www.giantbomb.com/steam/3015-718/forums/do-i-have-to-buy-a-game-twice-to-get-two-languages-534821/?page=1#js-message-5186086
You can request Steam to remove games from your account, but you would have to make a new purchase should you change your mind.
I don't know if you'll get the unc version from BundleStars, though; might be a regional thing.
http://www.giantbomb.com/steam/3015-718/forums/do-i-have-to-buy-a-game-twice-to-get-two-languages-534821/?page=1#js-message-5186086
You can request Steam to remove games from your account, but you would have to make a new purchase should you change your mind.
I don't know if you'll get the unc version from BundleStars, though; might be a regional thing.