Cosa Nostra membership "Books Closed"

I read where the "books were closed" to new membership from the early 1930's until 1954, and then they were closed again until the mid 1970's. Does anyone know if this is true and if not what time period were they closed and then opened again.

My belief is Carlo gambino and luchese closed the books once Vito genovese went to prison in 1959. There's alot of threads on this the books were closed basically all during the 60tys a few guys got made cause they were very close to a boss or 2. There FBI files nicky Bianco Ray patriarca guy but real close to Colombo got made at some special ceromony in some restaurant in lil Italy. There's a few other guys to think I read Christy tic.

I think the books were closed in 59 cause Vito genovese probaly made a ton of guys to keep control of his family well he was in prison and gambino probaly thought wtf shut it down. They thought someone might have inducted FBI agents to. Stabilize the family's.

From what I can tell there were years where the books were closed, even though there are examples of some guys getting made in a given year when the books were supposedly closed.

I believe the books were closed because anastasia and his underboss were accused of selling buttons. This gave them time to weed out those guys and ample time to cgeck out any new prospects.

What happened to all of the guys who supposedly bought buttons? Were they shelved?