That's just the origin marker for the halberd in Blender, sorry.Though the trident and halberd have similar top design, they're so clearly different it hurts.
Though it helps they have some different functions. The halberd is more often used like a boomerang/chakram at times, while the trident has a lot more thrusting power. They both are great for slashing actions.
Also, what is that orange circle on his right thumb?
I could see some slashing attacks in Smash for both though.