If you have already purchased the game on GoG, then you should be able to download the Mac version--yes. Those wouldn't be separate purchases; that's not how GoG does things. If the Mac version isn't available on their site yet, it's because they haven't uploaded it. We sent it to them a while ago, so unfortunately, we're in the same boat waiting for them to upload it. I'll see if we can contact them and get things moving though.