I'd expect a detailed manual to fall under the Missile Technology Control Regime, MTCR, which is kind of the sister of ITAR for the EU.
Honestly though, the information isn't all that juicy. What most people would find interesting has been out there for a long time. The hardware in any rocket looks basically the same since Saturn V, and the only remarkable thing about the software is that it's organized.
Is there anything you'd like me to point you to?