That's not entirely accurate, Gravano has confirmed Montiglio's presence at Castellano's house in S.I.
Also, the first mention in Murder Machine of Montiglio's involvement with Smack is on page 271. where it is stated that sit down was arranged between Nino, Paul Castellano, Chin Gigante, Montiglio and a "boss" from the Genovese Family New Jersey Crew, to whom Mat Rega and his father were related. In that meeting the elder Rega leveled numerous accusations against Montiglio based on his son's(Mat Rega)story that Montiglio had withheld $30,000 in Vig payments that Rega had paid over the summer of '82. He also accused Montiglio of dealing heroin in the Bronx, that's it. The primary source of Montiglio's alleged heroin use is Matty Rega with whom Montiglio had been close but was betrayed when Rega couldn't continue payments to Nino.
I have attached images of pages 271 and 272 for your review, if anyone has factual credible evidence contrary to this they should post it to corroborate their position.

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