I believe that may depend on the original state of the doors. That is, if the doors originally had peek holes and metal strikers. In the model by laws it does state that locks and locking mechanisms are the responsibility of the owners.
It also states that the only changes that can be made are those that provide for security. So peepholes etc would probably come under that. So if past owners have included things such as deadlocks, peepholes and any other features that provide them with secure locks and added security then it is my belief that these are additional and therefore the owners responsibility.
Unless of course the by laws of the complex state otherwise.