The prohibition has no effect on being able to verify the claim. If you were allowed to disassemble, what would you expect to get out of that? Assembly. You will always get assembly from a disassembler so doing that neither proves nor disproves anything. You would need the original assembly source to compare against. And if you had that, you may as well simply examine it to see that it is all assembly and assemble it to verify that it works.
Having the 32 bit sources available is enough for me to believe their claims about the 64 bit sources also being entirely assembly. Their decision to license 64 bit differently from 32 is a different question altogether though.
100 is the average of the population as a whole. But if you consider any subset of that population, ie. university/college graduates, the average of that subset may be significantly different from the average of the entire population.
That said, I find the claim that US college grads have an average IQ of 95 to be very unlikely. That would be saying that college grads are less intelligent than the general population.
A bug in the code is worth two in the documentation.