mid to late 80's or so. Call S&W and they will tell you when it left the factory.
what is the manufacture date of a .38 police positive special serial number b 81
You did not provide a serial number.
418306
1950
1954
1970
Impossible to answer without the serial number.
about 1919
about 1936 (I believe)
You can find out at Proofhouse.com
@ 1969
1980