You should list legal internships if they're relevant. For example, I did a summer job in Washington, DC. I did not do that with a law firm, but with the government. I just left that on my résumé. But was it a good idea? More than five years ago, you probably don't need it unless it's related to what you do.
One example I would give is I did an internship with the Department of Justice but in the Environmental section. I probably shouldn't have left that on when I was applying to work in law firms because environmental is not really related to what I was doing. So, it's up to you. But you should be careful in the internships also. You need to be careful about what kind of organization it is and so forth.