That is not accurate. 61.39 refers you to the requirements for each certificate and rating.
So, for example, for the private certificate, ASEL, you need to look at 61.109(a)(4) which says...
I think we have a difference in the interpretation of the OPs post.
I read it as the OP has completed all the requirements for the rating Superduck is seeking. However for reasons unclear Superduck was unable to perform the practical test with an examiner in the last 2 calendar months since his instructor made an endorsement for the practical test. So from my point of view this comes down to is he still ready for the check ride. The FAR isn't clear about what that means. Specifically, once the prerequisites are completed it says a candidate must have;
6) Have an endorsement, if required by this part, in the applicant's logbook or training record that has been signed by an authorized instructor who certifies that the applicant—
(i) Has received and logged training time within 2 calendar months preceding the month of application in preparation for the practical test;
So if he has all the requirements completed and due to something like weather just wasn't able to take the check ride. I think he can probably take a short flight performing some of the maneuvers for the rating and maybe some ground review. But by no means does Superduck need to redo everything listed in the requirements for the rating. What is needed is up to the CFIs judgement at this point.
PROVIDED, of course, that the CFI still feels confident that Superduck still meets the instructors belief of preparedness for the checkride. If the CFI is ok with doing some ground review and no flight, Superduck still meets the requirements for endorsement for the check ride per 61.39.