The question has been asked here before about courses of other lengths, and I'm sure this one is no exception.
If the course was a loop course, integral multiples of it are considered certified, so the answer would be yes.
If the course starts and finishes at the same point, the start/finish point is considered a turnaround point for an event that would run over multiple laps of the course, so in that case the answer would also be yes.
In both of those cases, the drop and separation is zero, regardless of how many laps of the course you run.
In the example you cite, since the start and finish are not the same point, the drop and separation change depending on the number of laps of the course you run, so you would have to separately certify the marathon distance.