If that's the O'Bryan I think it is, then the Mandy Rice-Davies Principle applies.
As for what is written into the requirements: Did the intel assessments of the late 1990s, as reflected in the final Joint Operational Requirements Document, correctly anticipate the capabilities of the S-400 and Russian/Chinese multi-band radar systems, including VHF Aesas?
The answer to that question is classified but I would cheerfully bet anyone a bottle of Woodford Reserve that they didn't.