Without the serial number about all we can tell you is 29-2s were from 1962 until 1982.
Nice gun.
Oops, I see the serial number in the title.
Should be 1980.
Very nice .44 Magnum! Two of my Model 29-2s have serial numbers that bracket yours...my 6" blued N631156 is 1979, and my 6" nickel N771902 is 1980. I would also think yours in 1980. Enjoy!