The last 99% model 840 Cooey (which means made in Canada for Winchester) I could find for auction sold for a dismal $105. 16 ga makes it more unusual, less desirable as a shooter. 16 just isn't that common anymore. Shoot it and enjoy it or hang it over the mantle.
Need the serial # to get the mfg date, but as I understand it Cooey made guns 1961-80.