See this thread
The BMW Navigator IV, V, and VI units will all fit in the factory GPS cradle position and allow use of the handlebar Scroll Wheel. Your '12 bike would have come with the older dash surround for the smaller Nav IV.
The Nav VI GPS will just drop into your existing GPS slot, and the Scroll Wheel will work just the same. It's faster to calculate, and sunlight readability is greatly improved.
The existing Nav IV Dash Bezel has a smaller opening, so it will block some of the Nav VI's larger screen.
BMW offers a few different replacement dash bezels for around $60, depending on your bike model.
The updated 46 63 8 382 723 Instrument Cover for Nav VI shows on the parts diagrams for GT, GTL, and B models. There's also an updated 46 63 8 382 724 GPS Cover Plate, but I never use mine.
2011-2016 models all use the above part number, while the 2017 GT/L has four color options, and the B has two color options.
The 2017-2018 bikes and all Baggers should already have this part fitted from the factory.