Sikboy1029: If they do I hope the music works, Best soundtrack ever.
May be tough. Normally GOG just applies a wrapper that makes the games play back compressed audio files from the HDD and it usually works flawlessly (and just shows how incredibly incompetent all those publishers are who release their classic games on Steam without music).
The problem with Outlaws is that the game requests CD2 at some point which has different audio tracks. I'm not sure they could perfectly solve that problem. It would either require the game files to be altered so that the levels that normally play tracks from CD2 would request different track numbers than originally OR they would need the wrapper to react to the request for CD2 somehow. I guess altering the game files would be easier but such changes to the game maybe beyond the scope of GOG's work (maybe also for legal reasons?) and I don't know how hard they would be to make, depending on how and where the game stores that information.
Btw, if you own the CDs you can create disc images of them and mount them in a tool like Daemon Tools. I did that and Outlaws played back the music just fine. Of course that method still requires you to manually change discs at the right point and isn't suitable for an actual digital release but it's good if you happen to be an owner of the game and are just looking for a way to get the music to run without having a disc in the drive.