Dand,
Your gun can't be a 24V, as the 'V' designation was for centerfires only, and yours is a rimfire. The side lever was an economy model introduced in the mid sixties for a short period. One of the ways you can determine age somewhat is that in 1964, they went to the barrel selector in the hammer, so anything without the barrel selector in the hammer, is pre-64. Of course, some older guns have been converted from the side selector to the hammer selector, so it's not a cut and dried way to tell.
If you want to determine the age of your fathers gun, look on the shotgun barrel, left side, near the receiver, you should see a small oval circle with 3 digits stamped inside it, 2 numbers and the last digit being a letter(You'll need a good magnifying glass, it's small). That letter corresponds to the year the gun was made, here is the Stevens/Savage date code:
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 X 1970
This is refered to as the Stevens Date Code, and it is printed in several price guides and other gun catalogs.
If your fathers gun is in excellent condition, and all original, it should easily be worth 325/350 dollars, I've seen them sell for that much on Gunbroker and Auction Arms. Not bad considering that in the early 50's he probably paid about $42.95 for it, LOL. For some reason the 410's seem to go for a premium over the 20 gauge in the rimfire guns. 22 Winchester Magnum over 410 is HIGHLY desireable, I saw one on gunbroker last year in pristine condition sell for 450 dollars.
Hope this helps you out some.
Sincerely,
Garry