2006-D ? On Letters

I cant really tell from the pics, but they look like gas bubbles.

Not gas bubbles, not on a 2006. Those basically ended in the 1980s. The method of plating the planchets is far better now than it was back then.

What you have is a weakly struck planchet that left some of the original planchet striations visible on the outer letters (very common) along with some 'milk spots' that wre left over on the planchet after being washed at the mint. These spots are very common and affect a coin's chances at getting higher than MS67 in grade...which is why for some years finding a coin that will grade MS68 at PCGS is very tought to nearly impossible.