First of all, there is no difference in patents before and after release. The patent does not change after it's filed as it is part of the application process and the claims of the document.
Second, just because previous patents of Nintendo, which may have focused on a particular aspect of the broader hardware/console/handheld, are more abstract, it does not mean that in this case that should be a knock against the photo. How many other ways would there even be of showing the patented non-rectangular screen? There's not that many variations of an oval-shaped controller. And adding in more physical buttons would be against the point of the screen in the first place.
Third, it would make a *ton* of sense for a devkit prototype to resemble the patent drawing very closely.