1. Whisk vinegar, molasses, garlic, rosemary and 1/4 cup mustard in a bowl. Divide marinade between 2 large ziplock freezer bags; add chops and turn to coat. Seal and chill for 2 hours, turning occasionally.
2. Preheat grill to medium-high (350°F to 400°F). Remove chops from marinade, shaking off excess. Set aside marinade. Brush chops with oil; sprinkle with salt and pepper.
3. Grill chops, covered, until a meat thermometer inserted into thickest portion registers 145°F, 5 to 6 minutes on each side. Transfer chops to a plate and cover loosely with foil; let stand.
4. Whisk set-aside marinade and remaining 1/4 cup mustard in a small saucepan. Bring to a boil over medium-high heat and cook, stirring frequently, for 4 minutes. (Sauce will be thick.) Remove from heat and whisk in butter until melted. Spoon sauce over chops, sprinkle with Gorgonzola and serve.