Marine Corps Emblem

[Jardo Opocensky, Jr.]

I was getting my hair cut today and my Barber asked what the red dot stood for in the left claw of the anchor. I was chagrined because I had no answer and no clue.
Does any one know what the dot stands for if anything?

[BenjaminBerkeley]

I think it's just the nail where the main part of the anchor is attached to the hook, or whatever you want to call it. Notice how the bottom hook is facing in the other direction.