Will GOG do the same for the versions we own?
Sadly, that's not GOG's decision.
So far, 2k has not announced any of the Mafia Remakes/Remasters for GOG.
... about the mess with the trilogy.
They also messed up the releases of Mafia 2 back then, let's see what happens.
I bought the game on DVD, every DLC as well.
Then years later they released the Digital Deluxe Edition for Steam, which was basically the same thing + Soundtrack.
Well, I didn't get the soundtrack. I even tried to buy the DDE, but Steam told me that I already owned it. Contacting support didn't help either. Steam said it was 2ks fault and they didn't answer.
Edit: another question: Does anyone know if the Mafia 2 DE contains all songs again or just the reduced playlist?
Some time before the release on GOG, quite a few songs were removed from the game, also some music was removed from Mafia 1 because the licences had expired (the music for both games can be restored using mods).