Your western field model 04M-489B was made by Mossberg.The Mossberg model 50 is the same firearm.These parts should be found at Numrich gun parts corp.They may be found on the web.
The Wards Western Field 04M 489B is a .22 LR rifle that was produced in the early 1960s. While the exact year of manufacture can vary, it is generally considered to be around 60 years old, given that the model was made during that time period. To determine the specific age, you would need to check any serial numbers or specific production details related to that model.
About the same as Mossberg Model 50, minus about 20-25%. (see explanation) Mossber Model 50 valules according to 26th edition Blue Book of gun Values are below. 100% 98% 95% 90% 80% 70% 60% $175 $150 $135 $125 $110 $85 $65 The Mossberg Model 50 was only built between 1939 and 1942. Western Field firearms have no real collection potential to date, and are priced by their shooting value rather than collector's value.