Rare vintage OMEGA automatic bumper 1940,s Mov. Ref 1835078. Ref 2577.9 Faulty

Vintage black Dail rare omega . Please note ot is faulty that the back case Ref 2577.9 seems to be for another omega watch . Sold as seen as repair for spares no return. Please ref the Images for photos. The back case is not in good condition. Size approximately 36mm