It's established that Tony's father, Johnny, died in 1986. Tony had only recently become a Made Guy, probably in 1983. Jackie was 5 years older than Tony, so its possible he was made earlier too.

Is it likely that, when Johnny died in 1986, Old Man DiMeo made Jackie Capo of the Soprano crew? While Richie had already become Capo of his own crew by that point? You figure Richie was jailed in 1990 and was already a Captain.

I ask because every scene Jackie in, in the flashbacks to 1995, it is with Tony, Paulie, Silvio and Pussy - every made guy of that crew. Even during the crucial sitdown with Junior, who brings along some of his crew. If Jackie had had his own separate crew, wouldn't a member or two have been there at the sitdown? Why would he need all of Tony Soprano's crew there?

Which leads me to thinking, is it possible that Tony only became a Captain when Jackie became Boss, and that between Johnny's death in 1986 and Old Man DiMeo's imprisonment in 1995, Jackie was Tony's Captain?