That's excatly what I mean. There were rumors about a all new glass design for the iPhone 7s. I just don't see that. If that should happen it will be as I said before where the design of the iPhone 8 will be used with different materials. It makes sense if you think about it:
They will use the experience they gathered with the jet black iPhone 7 to produce the aluminium band, so that there will be a seemless design. They use the knowledge of the ceramic Apple Watch Edition for their iPhone Edition and so on. And that would also "satisfy" all reports out there. There were reports of ceramic, then stainless steel, then glass and so on.
BUT there might also be the possiblity you mentioned: that the hole in the back is used for inductive charging. If you look at the pictures closely you can see that the hole is quite big. Bigger than the front facing Touch ID nowadays. So that could then be the new iPhone SE with that indicutive charging hole and the body of the iPhone 7.
I think we can come up with theories all day long, unfortunately we will just have to wait and see for ourselfs at the Keynote.
I still think that there are 3 models releasing this year, 7s, 7Plus and the iPhone 8/Pro/Edition, the only thing I'm not sure on is the name. I do think it's going to be a bezeless design as is rumoured for a while now, no home button, OLED screen and so on but not for the 7s and 7s Plus I think all of this will be on the 8/Pro/Edition. The 7s will be for those who don't want to or can't afford the price of the 8/Pro/Edition which is rumoured to cost $1,200