657-1

[Heavy lead]

I found a 657-1 Smith I laid away today, very tight gun, this gun is early I know that much and also has a stainless hammer and grooved trigger and square back grooved frame with the old style checkered combat concalvo alves stocks. Anybody out there know what vintage this is. Is this a pinned barrel or newer than that. My guess is early 80's vintage, but not sure.
Any help is appreciated.
Thanks

[9.3X62AL]

Pinned barrels were phased out between 1981-82, if that helps.