Mine does on the front. You could probably carefully squeeze it together with your fingers and fix it. If you've ever taken an iPhone apart they just pull apart. Probably just wasn't completely pressed together during it's final manufacturing process. I put mine in a silicone Apple brand case so you can't see or feel it with a case on it anyways so I just left mine alone.
If you can feel the edge of the glass like I described above I wouldn't worry about it. If you can feel the edge of the stainless steel then I'd consider returning it because I'd be worried it was assembled with too much force or the phone was out of spec.
Little things like this used to bother me as well, but then I had kids and now I understand what it really means to have things to worry about, lol.
I am 100% positive that I could find something wrong with any iPhone if I looked hard enough. But it really comes down to, if it bothers you and you want another phone Apple will most likely swap it. They aim to please.
I'm not sure my edge would even show up in a photo but I'd be happy to try to photograph it if you'd like to compare. I think the only reason you noticed it is because you can feel it is because you can feel the edge of the glass which is sharp. I tried to hold mine up to the light and see if I could see the edge, but couldn't.
