Exactly
Sammy didn't know Gotti that well when Gotti and Tommy Agro hit desimone

I think his two sisters just got married & lived a quiet life

As for other mobsters talking about it- Sal ubatz talked about him at length in his book. And how Gotti waited a while before whacking him over the Foxy incident

Sal claims Foxy's sister was in the house when Desimone killed her brother and that she told Gotti what she saw but I'm guessing Gotti didn't want to hit him right away....either due to that or something else