You will need to call SIG to find out.
You willl need to call SIG to verify, but, it is probably 2004.
what is the manufacturing date fo a colt diamondback serial number O72239
what is the manufacturing date of a marlin rifle model 1893 with the serial number D1624?
No way to answer without the serial number.
Your Marlin firearm was made in the year 1979,with the serial number that you have provided.
manufacturing company of combine can tell you year of manufactur from the serial number
1977
1942
1954
1980
1956
1995