Zero reason for this particular set of panels either side of Loki to be included if Sanji and Gaban's interaction was just supposed to be a gag in this chapter. It started out as one but Oda could have left it there. He didn't. Most obvious flashback bait of all time. First time I am firmly on the side of Sanji getting CoC, Gaban and Sanji's first interaction being about it is too big of a hint.