For Sale Ferrari BB rear hood

What's the difference between this hood and a 512 hood?

 

This post confuses me as the hood pictured has the additional vents on the sides of the top for a 512 which where not on the earlier 365 cars. But post says will not fit 512 so I’m confused.

Also are those standard arches? Hard to tell in pictures but might have wide body kit installed? The flat surface around the wheel opening looks a lot wider than stock.

 

That's a pretty ambitious 2nd post....

 

The correct term is "clamshell" for this part of the car. It's either a BB or a BBi clamshell. I can't tell which one from the pictures but I'm sure the experts can.