This model in particular, if manufactured after 1971 have the first 2 digits in the serial # that corresponds to a year dating back from the year 2000 (see http://en.wikipedia.org/wiki/Marlin_Model_60 for more information). For example, a serial # begining with 12 would indicate the gun was manufactured in 1988 (2000-12=1988), so your gun would most likely of been made in 1994. I own one of these model 60W rifles myself and would like to find out some more information concerning history, production and value.
Some sources say the Marlin 60ws with the gold trigger and brass medallion were made for distribution through either the NRA or Ducks Unlimited--I suspect the former is more likely, as it sponsors youth shooting programs. Also, I'd think a Ducks Unlimited edition would have a medallion featuring some sort of wildlife--like ducks!