While I understand that many applicant will use DO schools as a back up, they should actually have some type of interaction with a DO (many will be the same as MD). I personally feel that being able to work this into your personal statement (maybe in one of your experiences that led you to wanting to be an osteopathic physician) for your DO application will benefit you. Probably not necessary though. Like @Angus Avagadro said, you can work this in by utilizing the osteopathic term.