S & W manufacture date help

Model and Dash numbering system
--------------------------------
Model 10
-1 1959 Heavy Barrel
-2 1961 Changed extractor rod thread to LH on standard barrel
-3 1961 Same as above, for heavy barrel
-4 1962 Screw in front of trigger eliminated
-5 1962 1/10" to 1/8" front sight, on standard barrel
-5 1962 Screw in front of trigger guard eliminated on
heavy barrel model
-7 1977 Change to put gas ring from yoke to cylinder
-8 1977 Change to put gas ring from yoke to cylinder
on heavy barrel model
Model 12 1957
-1 1962 Change extractor rod to LH thread, eliminate
screw in front of trigger guard
-2 1962 Front sight changed from 1/10" to 1/8"
-3 1977 Gas ring on yoke to cylinder
-4 1984 Change frame thickness to same as all K frames
Model 13 No designation used to avoid confusion with air force model
13 air crewman
Model 13
-1 1974 Introduced
-2 1977 Change back to gas ring on cylinder
-3 1982 eliminate cylinder counterbore
Model 14,15,16,17,18,48,53 (all start without dash in 1957)
-1 1959 Change to LH extractor rod thread
-2 1961 Cylinder stop changed, hole in front of trigger
guard eliminated
-3 1967 Relocation of rear sight leaf screw
-4 1977 Changed gas ring from yoke to cylinder
19 All of the above changes and
-5 1982 Eliminate cylinder counterbore

Should read farther down -
Take a look at this thread, post#5 by SaxonPig - http://www.thehighroad.org/showthread.php?t=356710
I'm thinkin' your boy's sn falls in this range.... 7K26,044 – 7K70,577....1975

I'm thinkin' 1975

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