Barzini and Roth never met
This obviously can't be known, but Moe was mentored by Roth and did business with Barzini, and then the book mentions Barzini "had interests" in Cuba. So, very plausible they crossed paths.
Maybe so Pete it was just a play on Fredo and Ola never met
It occurred to me there was no mention of Barzini by Roth and Roth was unknown in Godfather
Also Moe tried to to business with Barzini
only when the Corlenes came to take over his hotel
