Yup, from what i understand the car will recognise the stereo that was fitted in the factory (no need to input a code if you disconnect the stereo for whatever reason) . If the stereo originated from a different car then the code is required. With my 07 Gti the code came with the car in the stereo manual . Earlier this year I retro fitted an RCD 510 removed from my neighbours Tiguan. But the code didn't come with his new car. In order to get the code he had to return to the dealer, have it hooked up to their computer and receive the code from the factory in Germany. This is probably as a result, allegedly , of a number of RNS510 being diverted off the factory line for the black market !!
