If the file isn't ever going to change, you don't need to lock it. It might be a good idea to change the permissions on the file to make sure, if w2k lets you do that. It will at least give someone pause when they come to update the file.

On the other hand, there's no strong reason not to read-lock the file, and it is a good habit to adopt. You never know when it might be updated by some other process written by some other person...