To the best of my knowledge acura hasn't changed the part since march of 98', though I could be mistaken in saying so.

The 2 door integra front bumper is the same in all integras, the lip is an add on piece. If it seems to be mounting slightly differently, you can bend the metal clips in the front corners of the lip, where the lip curves. Don't have any pictures, but it's a little bracket that can be bent which will raise or lower the lip ever so slightly.

I'd really need to see some pics of what you're talking about, it just sounds like it needs to be played around with a little...

Later,
Aj