At some schools, you only need one term of OChem lab. At others, you need to take it for an academic year or get a certain number of credit hours. Others let you substitute a term of Biochem in place of OChem II + lab. Yet others don't require OChem or lab, at all. The MSAR is vague on this point. Your best bet is to check the website of the schools you plan to apply to, though this source can be vague too, commonly saying "one year of Ochem with lab" (rather than saying labs). Some times you have to call the schools to know for sure.