So what happens if the user doesn't have that installed? Do the achievements just not work, or does the player get an error/crash? If the achievements don't work that's not the end of the world, but if it breaks the game then that is problematic.
Do more modern computers come with that installed already? If so, just how common is it (computers within the last 5 years? 10?) Needing GOG users to download and install another piece of software is a lot to ask of them, so if you could rebuild it with an earlier version that would probably be for the best.