Yes, and they've been testing the waters in offering mod packages for a while ... with some successes and others, well, not as much. Take for example the GoG cut of Daggerfall Unity. While initially it might have been a good idea (on paper), the reality is that the mods were still being updated, and the GoG cut fell behind and became outdated. GoG has had better success with offering whole conversion mods that are complete, and when the base game is no longer being updated. I don't know if GoG will maintain the modded games like they do with regular games - to keep them operable on modern systems. A few of the whole conversion mods have had numerous updates since initially offered, but I don't know if that is GoG's doing or if it is the mod developers stepping in like regular game developers to keep their listed titles current on GoG.