rickga: The .32 Double Action 4th model was made between 1883 & 1909 in the serial number range 43406 to 282999. Models made before serial number 209301 in 1898 are considered antiques by the BATF. To get an exact shipping date (and address) you would need to contact Roy Jinks at S&W and pay a fee of $50 to get a factory letter.
For the purposes of guesstimating your guns age, 22,232 3rd models were made between 1882 & 1883. Your gun is approximately 21,000 later in the serial number range, so if production levels remained constant your 4th model may have been made around 1884-1885.