And typos that really make a huge difference (such as lied vs died) are easy to spot while editing/reading and would most probably not occur in the final print.
Not when it comes to numbers. It's very easy to overlook the difference between 2367 and 2387. People do it all the time. The numerals 6 and 8 are so similarly shaped that it's easy for the eye to gloss over the difference. Someone who's read over the text a dozen times expecting to see 2387 may overlook it if it gets accidentally changed to 2367 late in the process. It doesn't matter how competent or conscientious the observers are; it's an artifact of how the brain's perception functions. People make mistakes like that all the time. Heck, just last night, someone in another thread on this very forum posted 2287 when they meant 2387. It's a very common kind of mistake, one that everybody makes from time to time.