I don't think that it will be available because the web browser sucks. If they make the firefox web browser available, than there will be more chances to have the adblock.
They can make a firefox web browser because it is open source. I don't like the Lg web browser because if you watch a 30 minutes video, after 10 minutes it says, "out of memory, app closed" and my friends Lg Smart tv without webOS and i can watch unlimited videos on the web browser and it never closes. Hope it helped, enjoy what you have and be patient.