You're right. They're not gang bangers, and they don't flash gang signs. Of course they're not "in a gang"; that's a stupid idea that took hold of fans who watched too many movies.
They do flash "209" signs. They're proud of where they're from.
Or, did. I haven't seen them do it in a long time. (In fact, have they thrown the 209 since they stormed out of the arena after Nick v Noons 1 in 2007? Did Nate throw it during his antics with Conor??? I honestly don't know; I don't watch the buildups anymore.)
They're more like the guys who are around the block who never actually joined a "gang", but have friends who did, and live by the same basic codes and ethics; #1 always back your homie, #2 don't talk to cops, #3 never back down, #4 earn respect, give respect, demand respect, #5 fuck you.