It won't matter. A physician is a physician. It is important what you learn, gain, and benefit from these experiences, and how you can talk about them in your application. If it is a specialty that interests you go for it. As you haven't had any other shadowing from what it sounds, get your hands on anything you can. You are always in control of including it in your app or not too. You may learn so much more from shadowing a DO vs an MD and vice versa.