It is a multiple choice test. Technically, you could walk in with zero knowledge of anything and get a 45. It is not, however, likely that you will get your desired 36+ if you walk into the test with a significant gap in your knowledge.
If you haven't taken organic chemistry at all before your MCAT prep, it will be a lot harder on you to prep for that material than it will be if you take the MCAT after taking organic chemistry. For myself, I took the physics for engineers and that sequence skipped optics, fluids, and sound. That part of my MCAT prep sucked and was an area in which, when I saw it on the exam, took me the longest to solve problems. I can't imagine have an entire discipline unstudied prior to the MCAT prep.