From the SCSW book, BEZ... probably, but not definitely, 1989 or 1990. I believe this is not a common gun, and you may want to consult the experts on what it may be worth.
My model 631, BEZ27xx was shipped on 2 May 1990. If you have the box your 631 came in, the special order code is the date shipped. The first digit is the last digit of the year, in your case it is probably a “0”. The next three numbers are the Julian date.
Mine reads 0122, so the 122th day of 1990 = 2 May 1990.
This is the revolver that started my love affair with all things 32 caliber.