What is the age of a Stevens Ranger double Barreled 12 ga shotgun SN C18685?

STEVENS DATE CODE Double barrel shotguns were date coded between 1949 & 1970. This code can usually be found behind the hinge pin or ahead of the trigger guard on the bottom of the frame and is a small circle with a letter and a number in it. The letters indicate the year of manufacture starting with "A" in 1949 and ending with "X" in 1970. The letters "O" & "Q" were not used.

Some say this code worked on their single shot shotguns as well, but this is not verified. It appears to have not been used on any other models. A 1949 I 1957 S 1965B 1950 J 1958 T 1966 C 1951 K 1959 U 1967 D 1952 L 1960 V 1968E 1953 M1961 W 1969 F 1954 N 1962 X 1970 G 1955 P 1963 H 1956R 1964