The taillight will work with the adapter harness without any VAG coding. I have a 2010 model and the main difference on how the taillights work between pre and post facelift for U.S. model is how the turn signal and brake light work.
Turn and brake work independent of each other
Turn and brake work in conjunction.
With a pre-face lift model, you will only need to code if you want the turn and stop light to work in conjunction like post-facelift models.
The part numbers 8R0945094C 8R0945093C you listed appear to be for EU spec taillights. Which have a yellow turn signal as opposed to US spec which are red turn signals. Since Pre-facelift coding is set to work indepedent you will be fine without any VAG coding. Only Post-facelift wanting to use EU spec taillight will have to chagne their coding from in conjunction to independent.
As for the adapter, Kufatec's adapter will not work with US spec vehicles. I had a member from another forum contact me to build him the correct adapter harness after he ordered the one from Kufatec did not work. If you notice on the photo of the adapter. The old connector is a 4 connector housing as opposed to the US spec 8 connector housing. If interested in a set of harnesses please PM me and I can give you further details. This is what the harnesses I make look like.