First off, it sounds like you do not know the true purpose of narrow banding, which is to ADD more frequencies within the given spectrum. All agencies using 150-512 MHz must narrow band their equipment by January 1, 2013, if not they will be subject to FCC action.
You can read more about it here: Narrow Banding
Second, all of the Clark County fire Departments have narrow banded already so most of the county is narrow banded. You can click on the license and look for the emission designation 11K2F3E which indicates they have or are in the process of narrow banding.
Your 996 will receive 700 MHz frequencies, just make sure you have the latest firmware installed.