I don't believe that's correct. I'm pretty sure Carlo was Anastasia's Underboss after the murder of Frank Scalise. Only for a few months though. Before then he was just a Captain.
It is pretty well documented that he was consiglieri.
Raven ive literally never heard Carlo was consigliere, only read that he was Alberts Underboss before he had him clipped?
"No, no, you aint alrite Spyder you got alotta fuckin problems"