Of course they didn't have a commission approval. Otherwise the Genovese/Lucchese - Gambino tension after the fact wouldn't have existed.

Gravano said they put out feelers with Colombos and Bonnanos, I think he even said Casso kind of said they wouldn't mind. They didn't even try with Genovese because Chin and Castellano were close. So they tried to get a sense of what will happen if they go ahead with it, but no commission approval.

Edit: I checked Underboss and this is what Gravano says about it.

Ruggiero met with Gerry Lang and Donnie Shacks from the Colombos. They were ok with it. Gotti said he had Massino in his pocket, because Bonannos at the time didn't have a seat in the commission, and removing Paul would increase their chances to get their seat back. Frank DeCicco talked to Casso who said he didn't give a fuck what happens to Paul. Genovese they didn't even approach.