Ratings aren't based on a course, they are based on the players that played league that night with established ratings history.
If you play a round of golf with 10 people that are rated at 1000, and your 60-950, and you play a round with 10 people at 900, you can bet your 60-will probably equal a 925 now instead.
Par is subjective, but has nothing to do with the ratings. There can be manual manipulations with weather related incidents, that typically will only occur when you have tee times that changed over the day (yet another reason Tee times are harmful for ratings.....or tough to be accurate with).
The issue that night was that you had 968 rated players shooting 68, and then 925 shooting 59, so the curve was that the course played easier to the system on the lower rated players, and thererfore the high rated players should have shot better. It again shows a "flaw" in ratings that I can go into but ultimately unless your higher rated players shoot better than you the course will play at a "lower rating" over all. You can look at scores from different pools of the Wide Open to also see that the variance based on course and pool is also different.
Ratings are far from perfect, it is what we use currently though and there will be issues based along those lines. Suffice it to say, par (the TD's determination of PAR) has absolutely nothing to do with ratings, it has to do with the players that are rated playing that course in that same field on that same day. Every day a course can be rated different based on the participation, even though the course doesn't change. What you hope to have happen is that you get enough people playing the same exact course over and over in the exact hole configurations (tough in KC as many placements on MANY holes make the course different weekly almost) so that you get a statistical numeration to have an understanding of the course.
I have done that at Cliff Drive over the years to learn which holes are tweaners, but then that is my own diligence. Not everyone enters the hole configurations to make determinations.
So the longer or longest answer (yeah I can be longer) is that it doesn't matter what course is played, as long as everyone playing that course played it that day under the similar conditions for rating purposes.