Hey Fireball, No disrespect intended, but yes, the 99 stocks can vary greatly in that area. In fact, all but one that I have had in my hands have the factory wood considerably proud of the metal at the top tang. All were pre-mil guns. One I saw was a "K". The reason I notice this is my desire to add a receiver sight to a 99, but never could figure out how to do it without carving out factory wood....which I would not do. My solution has been to use Marble's or Lyman tang sights. The bases can be carefully "sprung" to rise slightly above the stock wood at the back of the tang.
I am surprised that the sight makers did not relieve that area under the receiver sight bases to allow for "proud" wood. I am guessing if you wanted to ruin a sight for collectors but solve the issue, you could machine away the metal underneath the base where it conflicts with the wood.
My solution to the dilemma in your photo is to clean it up as best as possible, and put a receiver sight on there! Best wishes to all, and happy Saturday. Marc