yes, Djokovic used to be listed at 80 kg = 176 pounds for most of his career – and it's still what google automatically tells me – so they've indeed adjusted his listed weight. That said, most of the ATP stats are useless. There's no way at all Fed is heavier than Murray for instance. As for Noél, he's not morbidly thin or anything, so let's not get ahead of ourselves, but he surely has less mass by now than he optimally should. Most of all a certain amount of muscle is just good for injury prevention, and the way he looks now you'll wonder if he'll both be a bit less explosive and a bit less endurant.
Purportedly some players, upon seeing him in Melbourne ahead of the tourney, thought he was lacking his usual muscle tone as well. Might be true as Becker claimed that he hasn't really put in the necessary work. Skill level is still obviously there, but one thinks you can't stay top dawg if you're not putting in 100%.