Under NDA development it is frequent that you can't reveal information through "readable" function names or variables, or even comments explaining the limits of certain values, etc...
It is frequent, but this is not the case. Please read the relevant information about the contract. The people involved worked hard to avoid the trap you are describing.
And, strange as it seems, it is not _that_ unlikely for NDA contracts to allow complete freedom in released source code -- at least with smaller companies.
/alessandro