In a word, no.
There used to be an event north of Chicago called the Lake County Races. They had at least three races- a 10K, a half marathon, and a full marathon. All of the races started at one place at the same time, and finished at different places along the route.
By the time the event had "run its course", we had calibration courses near the start, 10K finish, half marathon finish, and marathon finish. At one time or another, we used them all, and almost always used more than one in the same measurement.
When we measured the Bank of America Chicago Marathon earlier this summer, we set a calibration course at approximately the halfway point. We calibrated on the calibration course near the finish, measured the first 14 miles of the course, calibrated on the new course, measured from 14 to the finish, then re-calibrated on the course near the finish again.
If you have a point-to-point course or a long out and back course, you'll get better results with more than one calibration course, especially if they're located at the extreme reaches of the race course.