He wasn't asking about genetics and he wasn't asking about where fat is stored. He's asking how things play out if you stop lifting and gain a bit of non-muscle weight. More specifically, is the muscle still there, but buried under the fat, or is the muscle lost?
You will lose the muscle over time, and the start time for it to be noticeable is around the two week mark and the muscle will go away more and more from there. You might notice a small bit of strength loss before the two weeks, but the muscle tissue is still basically ALL there. Even way beyond two weeks, there will remain some basic building blocks of that muscle, making it easier to re establish where you were. It will be easier the next go around than if you were trying to build that muscle for the first time.