It is virtually impossible to give a value on any firearm with just the model and serial number. You do not mention the finish, overall condition, barrel length, grip material, any accessories, engraving, papers, box or historical association with a person or event. It could be in the 10-1000 USD range or more.
About 1913 for a Colt police positive special with that serial number.
A Colt police positive .38 with that serial number was made in 1931 and a Colt police positive special with that serial number was made in 1928.
A Colt police positive .38 with that serial number was made in 1930. A Colt police positive special with that serial number was made in 1928.
A Colt police positive special with that serial number was made in 1964.
A Colt official police special with that serial number ws made in 1947.
what is the manufacture date of a .38 police positive special serial number b 81
A Colt police positive .38/bankers special with that serial number was made in 1934. A Colt police positive special/detective special with that serial number was made in 1928.
Made about 1972, 37 years old, for a Colt police positive special with that serial number
1958 for a Colt police positive special with that serial number
According to proofhouse.com a Colt police positive special with that serial number was made in 1957.
Around 1920 for the Colt police positive special with that serial number
Found a Colt police positive special C55457 made in 1973, no serial number starting with G.