Quick recap, we have a clear P-38 on the coming soon page but same kind of drawings have been misleading in the past.
We have that awkward not working link form their website: http://www.vmfa-531.com/leathernecksim/coming-soon/
We have strong clues towards the super galeb (Fact that some of the devs might have flown it, the super "bird", the serbian base, the aerobatics things)but imho that wouldn't be "special note" worthy surprise(s).
Oh, and we have rivets.
What am I forgeting ?