is bossk a legendary event?

I only had Bobba and IG88 worked on when dark side territory battles came. Bobba was briefly good when he first had his rework, and his ship is strong so there was reason to work on him for that. Ig88 I only had geared up because I used Droids in arena before zetas came and changed arena up, and rendered the faction obsolete. The others never had a use for me to work on them. I only had some starred up a bit cause nothing else to work on in stores or through bronziums. Never needed them for the scoundrel heists.