Jason is right, except that the Marlin Firearms Co was still producing unfinished Hunter Arms guns in 1945. They started putting the prefix S on in 1946 and the first was was for the president of the company Frank Kenna serial no FW S1 a Crown Grade. Also begining in 1946 no more Regular frame only Feather weights.
It was still a quality made gun, but nothing is or was as nice as the Syracuse made guns, not any maker.
Gun in question is from 1948.

David