Pre-1960 Gambino made guys...how accurate is info?

This is a question that came to mind from this other thread I started about the actor in Carlito's Way.

http://www.gangsterbb.net/threads/ubbthreads.php?ubb=showflat&Number=1010242#Post1010242

How accurate/complete is current day info on pre 1960 Gambino made guys? That guy said his father, Carmine Minucci was made. Let's say you're a book publisher or whatever, visit even possible to verify (one way or the other), something like that?

How many Gambino soldiers were there in, say, 1950?

Not only the gambinos
But it seems to be like everyone say that the 5 families had a lot more members
I wonder if it's accurate too...

I think the best estimates are the Gambinos and Genovese at the top with 300 each, and the other 3 with 120 spice if averaged out. The Columbos were the smallest in New York.

Traditionally it ran like this from the 1940-1970s era.

Genovese 250-300
Gambino. 250-300
Bonanno 175-200
Colombo 125-150 max
Lucchese. 100-120 max

It is well known that in their heyday the Lucchese Family was always the smallest of the NYC 5. Only in recent years they outpaced the Colombo's.

DeCavalcante 35-55

Not total numbers but I mean if you were trying to verify a story or history about someone from back that far, is it even possible if thet weren't ever mentioned in news media or anything like that?