I purchased from gog.com and used the gog downloader to download and install the game. I am early in the prologue of the game. Today I noticed on the official witcher site a list of DLC available, but I am not clear what, if any, was already included on the gog version. I noticed if you manually download the game, there are 6 smaller files to download and 1 large game file. Since I downloaded using the installer tool, I have no idea if I should download these smaller files - are they the DLC? Thanks.

send an email to each e-mail adress. You can use all of them.

GoG had no pre-order DLC.

Technically none. Your bonus "DLC" is being DRM free.

But, you can get all that other pre-order dlc by simply sending an email to the email addys on the community section of the main site.