I vote against the burn mark. A real restoration of the film would remove it, because it wasn't part of making or printing the film. It is damage after the fact. If someone had spilled coffee on the print, should the coffee stains be preserved too? No, it would be removed to reveal the film in its fullest original glory. If you want to preserve the sorts of damage that prints accumulate over their lifetime - burns, scratches, hairs, dust, mouse droppings, etc., there is another preservation that has that covered.