Cut small slits in leg of lamb using a sharp knife; insert garlic slices into slits.
Combine vinegar and next 3 ingredients in a large shallow dish or heavy-duty zip-top plastic bag; add lamb. Cover or seal; chill 8 hours or overnight, turning lamb occasionally.
Remove lamb from marinade, discarding marinade. Sprinkle lamb with salt and pepper.
Grill, covered with grill lid, over high heat (400° to 500°) 30 to 45 minutes or until a meat thermometer inserted into thickest portion registers 150° (medium-rare). Cool.
Cut lamb into 1/8-inch-thick slices; serve on Sweet Potato Rolls with lettuce and Raspberry Mayonnaise.