Everything will depend on the BS/MD program, they are all different and have their own sets of rules and regulations. So you'll have to ask the ones you are interested in independently.
As a piece of unsolicited advice, I strongly discourage students from BS/MD programs. Why? Because those who are competitive for BS/MD programs are also extremely likely to eventually be competitive for medical school through the traditional process. BS/MD programs often pidgeonhole students into medicine before they are capable for making an independent, mature career decision, subordinates the entire undergraduate experience into meeting the requirements of the program and moving on, and otherwise hamstrings the flexibility and opportunities to explore during undergrad which make getting an undergraduate education worthwhile to begin with. Finally, the BS/MD program could compromise your ability to receive scholarships or generous aid through the traditional process. Consider that before you choose a BS/MD.
