1. Cook wild rice and brown rice according to each packages directions. Cool and set aside.
2. Cook bacon in large skillet over medium heat until crispy. Remove to paper toweling to drain. If there is less than 2 tablespoons drippings in skillet, add butter or oil as needed.
3. Heat the fat in the skillet. If using the turkey liver, add to the skillet; saute until lightly browned, being careful not to overcook. Remove the liver to a cutting board. When the liver is cool, coarsely chop. Set the liver aside.
4. Add the onion and celery to the hot skillet, adding a little more fat if necessary; saute for 3 to 5 minutes or until softened. Using a slotted spoon, remove the vegetable mixture to large bowl. Add the wild and brown rice, bacon, liver, nuts and sherry, and the marjoram, thyme and salt if using, and the pepper; mix together well.
5. Cover and refrigerate the stuffing until ready to stuff the turkey. This is enough to stuff about a 12-pound turkey. Or spoon into a shallow 3-quart baking dish and bake in a preheated 375 degrees F oven for 45 to 50 minutes or until the stuffing is heated through.