If the module scripts are stored in a place like ServerStorage or ServerScriptService, than definitely no. I wouldn’t worry about people stealing your scripts either way.
If I understand, you are worried about exploiting, right?
A module script normally is placed in Replicated Storage, so, if you want to use it in a LocalScript it will be replicated locally and will be “visible”.
But it’s not that easy to exploit a game…
Yes if you want a module script that can be used in your local scripts, add it in replicated storage. All I’d suggest is to manage/split up your module scripts so that if there are ones that have server side logic only, keep them safely in server storage. Only put the code that you actually need to call from local scripts in modules in replicated storage.