Premed reqs provide background material for MCAT. You should have completed these courses prior to MCAT. Premed reqs are not typically targeted at MCAT prep. They are, in part, science courses open to anyone with an interest, premed or not. Agree with @ Creekland, when time comes, you’ll probably need two months or so in dedicated MCAT prep either on your own, perhaps a small group, or formal review course (eg Kaplan.)