I started studying for the MCAT without ever taking Physics II and also having been out of college for almost 3 years (so the last intro bio/chem/orgo class I had taken was 5 years prior). I had to teach myself all of physics 2 (electricity, magnetism, optics), and basically had to re-learn a lot of the other stuff, especially orgo.
I did not take a class, but I dedicated 2.5 months to studying primarily from ExamKrackers as my guideline for what is on the test, and using Princeton Review for more detailed learning needed for physics and orgo (and if I needed more help I went on the internet to a variety of sites).
So to answer your question - YES! I taught myself MCAT material for the first time exclusively from a review book, and I did well (35 - 12BS, 12PS, 11V)