If it is one of the original style with a screw through it, I seem to recall that Krieghoff International used to replace them at no charge due to the frequency at which they broke (usually right across the screw hole).
Well, since those older guns were more hand-fitted than today's production, a used one may have to fitted to your receiver anyway. In fact, it might be too narrow for your receiver's recesses. As I recall, having owned two Model 32 Vandalia Rib combos, one of which suffered a broken ejector, they want you to update your gun to the newer spring-retained parts. They might not even have any of the screw-retained parts on hand.