Yes however the question was can you make mods for CZ not can you redownload the HL source and make mods for half life and play them with CZ.
Further more I said according to the directory structures of the mod system EVERYTHING is considered a mod because you can select them in the mod menu selection screen. I only said CZ is a type of mod. CZ is a TC, that imo is a type of mod, however it is treated as a mod anyway by half life. Keep in mind the question asked was can "CZ" have mods and that is the question that I will look into. In other words I dont know if the source code will be released for CZ.
IMO CZ is nothing like SIN vs quake 2 because CZ wasnt started from scratch and you cant select sin in a quake 2 mods menu. Oh well thats just me.
Im sure you can make maps for CZ MODS on the other hand I still dont know.