The patina is fantastic!
As for the value, we do not usually discuss them.
Having said that, a quick ebay search will lead you to a couple of examples sharing the same dial as yours. Now, how collectable that feature is, is beyond me, but your watch has a great even patina and overall condition, which should help in fetching a premium over others.
As for the dial itself, I am inclined to believe that these might be the first run after the matte dial 16800 was put out of production. Nothing certain nor conclusive, just a hunch based on your open 6 date disk.
Good luck in your quest and enjoy your Sub!
Cheers,
Alex