So I'm already owning an old version of silver.

In my version u will always crash at the oracle where u aquire the map.
Or to be precise: You will always crash when opening the map which u will get at the oracle where you are forced to open the map.

Is this issue fixed in the GOG version?

Yes, that bug is fixed.

Well, since I'm not that far in the game I haven't tested it yet. But when I press F12 for the menu where all your weapons, items, etc are stored, it gives me a black screen. When I press F12 again, the game returns to normal and I can continue playing. Has anyone else have this problem? So far it is not game breaking or anything, but I'd just like to know.

Alright, that'll teach me to read the manual the next time. F12 is pausing the game, while going in the inventory via the pie menu works just fine. I don't expect any errors (aside from the dreaded bell-puzzle).

A good trip down memory lane this is!