Board Thread:General Discussion on Baldur's Gate Game/@comment-25751298-20191009062826/@comment-3234315-20191009115944

Yes, Baldur's Gate: Siege of Dragonspear is the only case where GOG and Steam installations vary from the one provided directly from Beamdog.

If it's about compatibility specifically for the Baldur's Gate II: Enhanced Edition, perhaps this is a good place for you to look, especially the first topic, List of BG2EE Compatible Mods.