The 15-Y was made from 1984-1988
The 15-YN was made from 1989-1996
It's now known as the 915-Y
Here's where you'll find all the other info you'd ever need.
http://www.rimfirecentral.com/forums/forumdisplay.php?f=20
your marlin was made in 2002-2003.
http://stevespages.com/pdf/marlin_15yn.pdf
Your Marlin model 15YN little buckaroo single shot,which was made in the year 1994 will bring between 80-110 dollars in the condition that you describe.
www.brownells.com
1988.
Year of manufacture for a Marlin 880 SQ, 1996
The model 36 Marlin rifle was made from 1936-1947.
Your Marlin model 780 was produced in the year 1977.
Your Marlin model 781 was produced in the year 1975 with the serial number that you provided.
With the serial number that you provided,your Marlin model golden 39A was produced in the year 1964.
With the serial number that you provided,your Marlin model 25 was produced in 1975.
The original Marlin model 444 was produced from 1965-1971.