How do Default Assignment Rules work if not originally set up on the course?

Summary:

We have a course that was not originally set up with Default Assignment Rules enabled that now needs to have the option to be retaken. We have thousands of voluntary completions against the course (self-paced offering with SCORM content). Will the default assignment rules alone work to allow learners to retake it? Or would we need to set up an initiave with a criteria of those in ocmplete/bypass complete status for course OLC123345 to be able to retake it?

Version (include the version you are using, if applicable):

24A (11.13.24.01.0)