Ironically enough Apple did build an iPhone with a glass back several years ago with the iPhone 4 and iPhone 4S, although at that time they did not come with wireless charging. Then then removed the glass back for future models, which like we said is ironic since wireless charging started becoming a more popular feature then.
In any case the leaked photos also reveal an interesting feature: the headphone jack. A recent rumor claimed that Apple would ditch the headphone jack on the iPhone SE 2, and given that Apple has pretty much ditched it since the iPhone 7 and 7 Plus, this would not have been surprising. However the photo suggests that Apple might be keeping it around.
It is possible that what we’re seeing is an early prototype, or it could simply be a fake. Either way it’s probably best to take it with a grain of salt, although do check back with us come WWDC 2018 which is when Apple is rumored to officially announce it.