Carbon fiber can't be inspected like metals can using radiographic, liquid penetrant, or magnetic particle testing, so even if we did know the exact materials and precise dimensions [1], it's very hard to characterize them and how they responds to stresses.

[1] composite materials are not as homogeneous as metals are, so most of the time we actually don't know the exact materials and precise dimensions. Only manufacturers that make enough parts to afford to do destructive testing can characterize the process enough to make reliable guarantees about part strength.