The good thing of a composite airframe is, that you can not build prototypes or test samples "by hand to finer tolerances". You need production tooling, you need production molds and mandrels. Additionally hand layup will never ensure finer tolerances. So we can be quite sure that the 787 test samples are very much like the early production airplanes. Since then, the design has been refined of course, affecting the newer serial numbers.
Anything with respect to humidity and fire resistance should be very close to the tested condition for any new 787.