I'm sure it seems like Golfs have become more rattly over the years for some reason. Trying to pinpoint odd knocks and rattles from interior trim has been the bane of my Golf ownership (on my 3rd), oddly enough my mk5 was fine, my 2015 mk7 was very rattly, my current 2016 mk7 seems to develop one randomly, and slamming my knee into the driver's side knee area or randomly banging on the centre console sometimes seems to work (sigh). Currently suspecting the area above the rear view mirror (sigh again)
The hunt continues...