Nice piece of family history!!!
Found this on http://www.go2gbo.com/forums/shotguns-and-wing-shooting/savagestevens-model-94-series-m-410/
You need to look for a very little circle, or oval stamped on either the barrel, or receiver, usually on the barrel, near the receiver, sometimes on the outside of the receiver, but never on the inside of the receiver. It is very small, sometimes you need a magnifying glass to make out the number(s) and letter. The letter is the date code key, if you can find the letter, match it to this, and you have the date of manufacture.
Stevens / Savage 24 date codes.
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A 1949 B 1950 C 1951
D 1952 E 1953 F 1954
G 1955 H 1956 I 1957
J 1958 K 1959 L 1960
M 1961 N 1962 P 1963
R 1964 S 1965 T 1966
U 1967 V 1968 W 1969
X1970