One of the Durable Myths of Mafia is that you have to kill someone, on orders from higher-ups, to be inducted. How many of the bosses named actually killed one or more people with their own hands in their "line of work"? It's not possible to know for sure, but it's obvious, for example, that Anastasia, Genovese, Persico, Colombo and Gotti did. But, I wonder about many (most) of the others, particularly the old-timers like Charlie Lucky and Uncle Frank.
There was a steadfast rule, up until a few years ago. that a recruit had to have put in 'work,' in one way or another before he was 'brought in.' Being the actual shooter, driving the crash car or backup car, setting the victim up for the kill, getting the weapons to be used, disposing of the body, acting as a lookout, etc. Not everyone was necessarily 'on the murder' scene.
And most members (most, not all), especially the 'old-timers' as you say, all 'made their bones.' Some, many times over, in fact.
Were there exceptions? No doubt there were. Many times, relatives of guys, such as sons, brothers, cousins, grandchildren, were sometimes given a 'pass' on such things. Especially if they knew a guy wasn't prone to that sort of thing to begin with. Also, there were so-called "earners" who were also not recquired to get their hands dirty. Their value was in their moneymaking abilities, not their trigger finger.
But I suspect, with few exceptions (if any at all), that fellas who became the actual bosses of Families did some 'work' during their lifetime. Otherwise, I don't think the rank-n-file under them, especially the top gunsels of a borgata, would have followed their lead. These are not soldiers were speaking of, or even capos for that matter. To have risen that high in the hierarchy, I would imagine the overwhelming majority did their share of 'dirty work.'
