Yeah you really don't need to memorize the top 200! I was freaking out about the test, because it seemed like there was SO MUCH that needed to be memorized, but I basically went in not really knowing anything besides how to do the math part, and I passed. I think the passing threshold for the test is really low... so I'm sure it's very rare that someone fails.
However, if you memorize all the top drugs, you will be super prepared for your first tech job. I just started as a pharm tech, and it's definitely challenging not knowing the top 200, C2 drugs, refridgerated drugs, etc.