What you've heard is very accurate, jump. Biochem and embryo don't have much of a representation, although do appear. For instance, the first question on my COMLEX was on hereditary fructose intolerance, so my advice would be to know the pathology found in these sections in First Aid.
Pathology is, of course, huge - especially reproductive and OB/GYN (lots and lots of bleeding vaginas). Micro is huge, although tends to test extremely esoteric facts and exotic bugs. You're right, a lot of it is not in FA. OMM is a good 20-25% of the test, though for the most part very simple. People tend to consider these free points that serve as a buffer. What's in the Sevarese is more than enough. I can also post a condensed study guide that'll have 90% of what you'll see.
For now, just hit FA and question banks hard. If you're a fast reader or have already gone through a qbank, you could try throwing in another pathology resource. RR or Goljan audio are always popular choices. Kaplan videos are fairly long but quite good. Pathoma seems to be hot ****. Pick one and stick with it, cover-to-cover.
The COMLEX mean score is 500, so at 477 you're pretty close to but still below average. The good news is that with a month of dedicated studying ahead of you that score can easily jump up 100-200 points.
