Based on the AAMC content outline, it is unlikely you will need advanced stats to do well on the MCAT. You will probably get away with not having a dedicated statistics class too. If you can take one, go for it, but I would not go out of your way to find a stats class at least not right now. What little stats the AAMC has reported is "testable" and what has already appeared on their practice materials is fairly simple and conceptual.
Understanding the basics of statistical significance, correlation vs causation, common error types, variance, and statistical biases are likely to be tested over and over. Statistical design and considerations seem to me more important than just doing stats or calculating anything.
Time will tell, but the AAMC will likely treat stats the way it has treated most math and calculations. A solid understanding of the concepts >>>> any ability to crunch numbers or pore over minutiae. Be prepared to decipher stats presented in tables, figures and graphs. What the numbers tells you will be way more important than HOW they arrived at those numbers.
Good luck!