You will need to include the whole serial number to get the answer that you seek.
1990.
1993
1991
That sn does not follow Browning's convention. Call Browning.
made in 1993
11 years old
The 2 letters NZ at the end of your serial number indicates that your Browning 325 shotgun was made in the year 1991.
Your question cannot be answered without you providing the full serial number to your browning.
This gun was made in 1989
23 years old
1994