The lack of any discussion on this in promotional material has made me consider this - could this be the first generation without version exclusive Pokemon? By this time last gen the Pokemon website was already noting several pairs of version-exclusives.
The 12-hour difference could be to limit "version" exclusives to day/night cycles - meaning it would be easier for certain players to obtain a certain species in one game over the other, but not impossible. The only examples we've seen so far of implied version exclusives have been tied to time of day - A-Raticate for night and Gumshoos for daytime.
It's possible that only Lunala and Solgaleo could be the true difference between the two versions . . .
The 12-hour difference could be to limit "version" exclusives to day/night cycles - meaning it would be easier for certain players to obtain a certain species in one game over the other, but not impossible. The only examples we've seen so far of implied version exclusives have been tied to time of day - A-Raticate for night and Gumshoos for daytime.
It's possible that only Lunala and Solgaleo could be the true difference between the two versions . . .