Personally, if you've been up and down those stairs and aren't tripping (and aren't a perfectionist), Why stress yourself over it :)

The stairs are probably within code which, as I recall, generally requires that there be less than a 1 part in 48 slope. A 12" deep tread could have up to a 1/4 inch rise/fall from front to back and still meet code. And I've actually heard people say that having the tread very slightly sloped (with the nose end slightly lower) actually makes the stairs more comfortable to climb.

Personally tho, I would be concerned that having the nose end slightly lower than the back of the step might increase the chances of having your feet slip out from under you when coming downstairs...especially if the stairs will hardwoods and your family is in the habit of running around in their socks without shoes on.

Falling on the stairs is NOT FUN. I just slipped on my stairs last week while coming downstairs without my shoes on. I still have a HUGE ugly and very painful bruise on my gluteus maximus from hitting the nose of one step hard as I fell. And I only bounced two additional steps downward from that point before I reached a landing. (Felt every bounce. LOL!) I'd hate to imagine what condition I might be in if I had fallen down an entire flight of steps.

But, if your stairs are going to be carpeted, or if you don't tend to run around in sock-feet like I do, that 1/8th difference from front to back probably isn't going to matter.