That is interesting @hahnmgh63. I would have not expected some cars to have one set of parts and others be different given our low one-year run of RS6 vehicles.
The '*-AR' unit did not work on my car. The AC did not work. It was stuck on 'Eco' mode and when I went over 45 miles/hour it would let warm air into the cabin even with the climate control panel entirely off. I would have to close the vents.

For any folks that need a unit, it probably makes sense to check which part you have using Vagcom if available, or simply just remove the radio to check it if you do not have Vagcom.