How late do rewards seats get released?!

Hi all
Flying out with my wife to the US on Thursday 12th September - already booked in Economy and looking to use my miles to upgrade us to Upper. Have signed up to Reward Flight Finder (which is a great resource) but nothing released yet for our dates.
When I do a dummy booking, I can see that there are still 12 seats available in Upper on the outbound and 15 available inbound. Is it usual to have so many available this late?! Obviously I will be on it if and when I get an email from RFF to say they are available, but just wondering if its worth me ringing up VA to see if they'd do anything.
Worst case scenario (if seats are still available) we'll have to try and upgrade on the day at the airport!
Thanks
Jack
Flying out with my wife to the US on Thursday 12th September - already booked in Economy and looking to use my miles to upgrade us to Upper. Have signed up to Reward Flight Finder (which is a great resource) but nothing released yet for our dates.
When I do a dummy booking, I can see that there are still 12 seats available in Upper on the outbound and 15 available inbound. Is it usual to have so many available this late?! Obviously I will be on it if and when I get an email from RFF to say they are available, but just wondering if its worth me ringing up VA to see if they'd do anything.
Worst case scenario (if seats are still available) we'll have to try and upgrade on the day at the airport!
Thanks
Jack