I think yes, newbies are entitled to join on any campaigns except signature bounty campaigns since they couldn't wear any signatures in the forum.
And as long as you meet all the requirements such as number of friends of followers and other requirements.
Facebook, Twitter, blog, YouTube, Telegram are some of the bounty campaigns that newbies could join but it all depends on the bounty manager because there are more bounty campaigns that only accept at least jr. Members only.