Our whites are pretty spotty this year also. I think it is a certain type, maybe post oak, that are dropping. We only have about 3 reds after oak wilt and the drought, which also killed all the blackjack. I found a loaded red next to a massive persimmon, which is where I will probably be opening day.
Only native oak I could even possibly see "naturally" dropping an acorn right now (and it would be rare) is a Chinquapin. They usually start dropping mid-September through first couple weeks of October.
If your acorns that are on the ground are green they are aborting or were blown out by a big wind event...
Post oak acorns are one of the last acorns to drop and in our area I don't think they made this year which is actually good from a deer hunting standpoint...
Oak wilt dealt our property a number as well because we have lots of skeleton's of massive red oaks throughout our place but a few did make it and of those few all of them are loaded...black jack oaks all died on our place - none left.
If those red oaks or persimmons are dropping around the opener it could be good. Put a camera in there and see.
Our White Oaks start dropping right at the beginning of October with our Red Oaks about 3 weeks further out to begin falling...