According to this leak https://www.macrumors.com/2016/03/14/leaked-iphone-7-images-reveal-new-design/
For the 7 (dual lens is said to only be on the Plus or perhaps Pro) the opening on the case lines up to the larger single lens in the leak.
This would suck. I already want OIS, but hate the larger phone. If the 7plus has dual cameras and the 7 doesn't I think I'd have to go larger though. I really don't want to have do this.