Raimey,
FWS guns were made from 1945-1950. FW means Featherweight, the E means ejectors. The gun has no "S" in the prefix and thus isn't a gun produced by the L.C. Smith company while owned by Marlin between '45-'50.
Trap grades were introduced in 1913 and were discontinued in 1939. The serial number 42709 puts this gun as a 1921 era gun and it was ordered by Von Lengerke & Antoine, Chicago, IL verified by a Cody letter showing the gun is in the original configuration as it was when it left the factory.
