When the letter is signed John Smith, DO not John Smith, MD the ADCOMs are fairly certain you are applying MD and DO. No one is saying that shadowing a DO is not good or equal experience to shadowing an MD. Don't get so defensive. The point was about the letter. Based on the OP's question, the allopathic adcoms will be clued in that the OP is probably applying MD and DO. Whether or not this is the case, or whether it is a positive or negative thing, no one really knows. However, appearances are everything.