Posted June 08, 2021
Cadaver747: I think Baldur's Gate Official Soundtrack is a standalone item, same goes for Baldur's Gate II Enhanced Edition Official Soundtrack. As for the Baldur's Gate: Siege of Dragonspear - Digital Deluxe Edition, yes it does not add Official Soundtrack item as owned which I also bought separately.
The Dragonspear Deluxe Edition does include both soundtracks, take a look at the goodies section: https://www.gog.com/game/baldurs_gate_siege_of_dragonspear_digital_deluxe_edition
Baldur's Gate: Siege Of Dragonspear Soundtrack (FLAC And MP3)
Baldur's Gate: Enhanced Edition Soundtrack (FLAC And MP3)
From what I can tell the two soundtracks are the only difference between the normal and deluxe versions of the game.