This is an interesting question in that it assumes that Jem and Scout show respect.
There is nothing explicit about the respect that Jem and Scout pay to the people of Maycomb. They are merely children. If anything what is underlined is how they don't show enough respect. For example, they do not like Mrs. Dubose. Scout says: "Mrs. Dubose was plain hell." They also do not like Mr. Avery. For instance, they make a snowman that resembles him in a negative way. Atticus makes Jem and Scout change the snowman, because the caricature was not respectful.
The only person that they really like is Miss Maudie. In light of this, I would say that they are not quite known for showing respect.
With all of this said, Jem and Scout are respectful in a general sense. They are southern children with good manners from a cultural point of view.