1975
No published sn data in English I know of.
Your serial number indicates that your Winchester model 61 rifle was made in the year 1938.that year Winchester made 5,991 model 61 Winchester,s.
Sweden
The first model 61 winchester was made in 1932.They made 3,532 during that year.
With the serial number provided,your Winchester model 61 was made in the year 1956.
1976
Sweeden
1956
In the low end Husqvarna manufacturing plant in Low End Alabama.
The last year of production for the Winchester model 61 was in 1962.They made 10,661 rifles that year.
With the serial number that you have provided,your Winchester model 61 rifle was made in the year 1961.