As andremop says, it's not a 3D software error, if someone was skilled enough to make the handheld model a simple stack of books would not have such an obvious mistake (hell I could do a stack of books)
However it still looks like a 3D CGI mock up to me..... that doesn't mean it's fake though, pretty sure Nintendo are allowed to use 3D rendering software. Though if the guy who made it has since said it was an April fools then that pretty much does mean it's fake.








