I have seen offer on their site but was not quite sure what to make of it?
Some fellows told they can't patch VI one by Mok's .
So what this version is ?

I bought the millenium edition of MMVI, and that worked with the patch found here
You just replace the exe. file. Easy enough, and it should work with the GOG game, if there was a problem.
But I do think that GOG would have taken care of that bug, before selling the game