Look on the butt of the revolver
Need a better deccription. Is it single action(cowboy gun), or is it double action(police gun)? Do you know the model name?(should be on the barrel) More info gets better answers.
Need a better description. Is it a pistol or revolver? What are the markings on the barrel or slide? is it a single action(cowboy gun)? is a double action(police gun)?
Check the butt
That model was produced in 1922.
police positive special made about 1920
The Colt police positive .38 with sn 8707 was produced in 1906.The second year of production.
1929
37 years old. A Colt police positive special with that serial number was made in 1972.
If your Colt official police is chambered in .22cal?Then it was made in 1937.
under double action model made about 1920
Impossible to answer without a detailed description of all markings, features, barrel length, sights, grips, box, papers, accessories, condition, type of action, etc..