Full disclosure: I haven't read either of these books. I can only assume they are good because of the many recommendations, but can't tell you how much better they are than the rest or where they are particularly strong.
That being said, I would definitely not consider failing to read these books as any sort of blocker or deal-breaker when it comes to your test preparation. Sure, they may be great resources, but so are several other options out there. For example, I consider the exam simulator to be a great way to prepare, but there are certainly a lot of people who passed the test without it (just as I passed the test without reading those books).
If you aren't feeling confident about your grasp of the material, that's certainly something to consider with regards to any decision to postpone the exam. But if you were feeling confident before finding out about those books, don't let that throw you off your game.
My recommendation would be to take a couple of tests over the weekend (one per day - more than that is counterproductive) and pay attention to the patterns in your results. If you find that you are consistently missing questions on a certain topic, then you may want to revisit that in your existing resources, or even pick up one of those books you listed for a new perspective. But let that be a targeted approach - you probably don't need to re-read the entire body of knowledge, so don't waste energy reading a new book cover to cover if you know you're only weak in one or two specific areas and have a good understanding of the rest already. Spend your time wisely and focus on areas with the biggest opportunities for improvement. Your scores suggest you've probably got a solid foundation to build on, so you probably don't need to start over at this point.