Firearm manufacturers usually etch the serial number on the top of the barrel near the bolt handle on a rifle or on the side of the frame on a pistol. This will tell you the year of manufacture for your Ruger firearm.
Den Serial Number Lookup 'We do not rise to our expectations, we fall to the level of our training' Archilocus, Greek Soldier, Poet, 650 B.C. Fortunately, 1955 to create a bell concerning the most popular revolvers on, ruger bearcat single-action revolver.
This was in 1962 at about serial number 42,600.