Measurement data must be submitted before the race takes place for the certification to be effective on race day. There is no "after the fact" certification. However, for record purposes, I believe a verification ride can be done (by an assigned verifier) of the course as run on race day.
I know of one case where the runners took a wrong turn, so did not run the certified course. But a verification ride was done of the course they did run, and it was found to be long enough, so the record stood. That was a long time ago and the rules may have changed since.