While Nathaniel Chambers (the composer) and Wadjet Eye Games (the publisher) are in charge of this, I have to assume the answer is no. Part of Nathaniel's arrangement with WEG was that he would be able to sell the soundtrack and keep the proceeds. As it turned out, however, the soundtrack's release was substantially delayed relative to the GOG release, such that most of the people who would've bought the soundtrack simply got it bundled with their GOG purchase. Even after the soundtrack was released, I remember seeing posts on Twitter and Reddit and the like where people would ask about buying the soundtrack and be told by others to simply buy the game on GOG instead. As a consequence, the main (and maybe only?) reason to buy the soundtrack in freestanding form is the lossless quality. If GOG purchasers got it for free (or for a discount), I imagine Nathaniel's sales would suffer even more.

In short, while I have no stake or authority in this, it seems that for Nathaniel's sake, it probably would be best to keep the two separate, despite my overall desire to see that fans get whatever we can give them.