Western Field was a Ward's brand for a wide array of sporting goods they sold.
They sold shotguns, rifles, bow, etc, and used several companies to produce the items under the Western Field name. Shotguns alone were produced by several different gun manufacturers, as were the rifles, as were the bows.
Assuming that there was never actually a "Western Field" bow manufacturer, and I do not recall ever hearing of one, the bow was probably built for Ward by any one of many bow manufacturers and you may never know which one made the "Bruin," but likely made by a quality bow manufacturer.
As important is the quality, and primary, is whether the bow is correct for you regarding draw-weight of the bow and your draw-length vs. bow length. A good deal on price might just end up not being a good deal in fit.
What are the specs (draw-weight @28" and bow length)?