1. In open roasting pan, place lamb rib roast on rib bones. Sprinkle with salt. Insert meat thermometer into center of roast, making sure pointed end does not touch bone.
2. Roast lamb in 375°F. oven 50 minutes. Meanwhile, in small skillet over medium heat, in hot butter or margarine, cook bread crumbs until golden brown. Stir in chopped parsley and oregano.
3. Remove roast from oven; spread top with mustard; Sprinkle crumb mixture on roast and press onto roast. Roast about 25 minutes longer or until thermometer reaches 140°F. for rare (about 30 minutes per pound) or until of desired doneness.
4. When roast is done, let stand 10 minutes for easier carving. Cut off backbone from ribs. To serve, carve between ribs.