Possibly.
Although if we assume he talks about his appearance, the way Luffy behaves himself, and what he does while still being a Pirate. I totally agree with Lucci.
To a degree, yes, but I think it is more along the lines of Luffy just doesn't have the aura and reputation about him. When you think of a Yonko, you think of someone who strikes fear into the hearts of most Pirates and Marines alike. Someone, where even the strongest of the strong think twice about how they want to approach and altercation with. Luffy hasn't garnered that reputation yet. The newspapers just said, "Hey here's one of the new Yonkos", and while that might work and strike fear against the common people of the World, those who have established a reputation of their own, need more than just "Extra Extra, here's a new Yonko." For Luffy to truly be considered a Yonko, he needs to prove himself, and earn that reputation that would make anyone think twice before fucking with him and his crew.