[dgludwig]

Poly-Chokes (and Cutts Compensators) were pretty popular "after-market" add-ons before the advent of screw-in chokes ("Winchokes" were first introduced around 1969). Your Model 50 appears to have some decent figure in the walnut and looks pretty darn nice, I'd say. Certainly a steal for what you paid; imo, it's worth at least twice that and likely more.
The add-on recoil pad (at least, I'm pretty sure it is) doesn't help the value but then, neither does the Poly-Choke.
Do you plan on hunting with it? I sure would if it were mine. Ought to make for a nice handling upland gun and I love the classic Winchester looks (especially compared to some of the ugly, ponderous looking stuff on the market today).