Scouts were made from 1957 -1971.They were first available with dual cylinders in 1964,they could also be had with a single cylinder.The early guns will say .22 LR or .22 magnum on the barrel.The dual cylinder models(1964)will say .22 cal. When the dual cylinder models were added to the line,the muzzles were all crowned to designate a .22 mag gun,the .22 LR guns previously had a flat muzzle.They were made in nickel(known as K-Scouts because of the "K" serial number prefix.These nickel guns all were made of a heavier alloy and had walnut stocks standard from the factory. Walnut was also available for an extra $5 on the blue models. A 1961 gun would have been a single cylinder only,that year is cool because it was Colt's 125th anniversary and all of the guns came with a special commemorative medallion.There were 4 factory finishes for the Scout,Duotone/blue/nickel/and "Midnite Black",the later was sort of like a black paint that was applied on the heavier alloy frames used for the "K" Scout. These are known as "62 Scouts" and came standard with plastic stag grips.There were many more changes through the Scout years,the early guns did not have pinned barrels,later they did, etc.