It still works fine. You need to close at least the cook window, preferably the entire devkit BEFORE you edit the Mods.DB file or it doesn’t save.
The GUID doesn’t really matter. Basically it sets the “version” if you will. When you update a mod and click “reset mod guid”, all it does is force the client to need the same version as the server. IE: if you reset mod guid, people can’t connect to server until the server also gets updated to the current mod version. Has nothing to do with that actual mod id.