Greetings! I apologize for delayed reply, but I was trying to get answers directly from the devs.
The short answer is: no. Not right now. Unfortunately GoG has some under-the-hood issues that prevent this from taking place. I'm not very versed on any of it myself, but the ball is in GoG's court and there's nothing Rebellion can do on it for now. :(
Can you tell us what this issue could be, what prevent GOG to distribute a freaking .dmg file with a game?