using dir_fd=None in some functions

[Gribouillis]

my question is, does specifying dir_fd=None count as not using it? or must that option name really need to be absent to count as not using it?

This is implied by the function's documentation. The signature os.lstat(path, *, dir_fd=None) means that dir_fd defaults to None. It means that not using dir_fd it is equivalent to using None. You need to check the doc of each function for which you want to do this.