I always associated the Lupertazzi's with being the Gambino for several reasons. First being the Rusty Milio hit which was basically a reenactment of the DeCavelcante's (Vinny Ocean) hitting Fred Weiss as a favor to John Gotti in 1989. I think Chase even said that scene/hit in the series was loosely based off of this event. Second, another little tidbit that I picked up on was when Meadow was reeling off Mafia history in front of her family at the dinner table and she listed off four of the five real life families with the Gambinos being the one family not mentioned in the four (she did not list the Lupertazzi's in those four either). That says to me that the Lupertazzi's would have been that 5th family had she listed all five and since she didn't list the Gambino's then that would mean the Lupertazzi's/Gambino's would have been that fifth family. Like someone else said above Tony also mentioned Johnny Sack's family as having "200 button men over there" which can only mean two families and with the Lupertazzi's being based out of Brooklyn and Queens in the series that would air more on the side of the Gambinos than the Genovese. If I had to bet, smart money would be on the Gambinos.