Apparently, gog does not get the source code for games. They use old CDs that they can find on ebay. I wonder if they could ask the community for CDs of games they can't find?
They mentioned that a few times. And you know why? Because those scumbag right holders never bothered on storing those! Honestly, we need a gaming museum for the source codes.
Pirates and the used games market (remember, those to "destroy gaming") did more for the preservation of games than most of the freaking companies!