Huh, not sure where else to post this, I stumbled across this documentary video of the Porsche 917.
Starting at the 3:23 mark, the cars of that particular year are gridded up and begin a pace lap. Considering the incorrect cars that are lined on the grid, this is not a proper Le Mans race.
What is this "race", why is it taking place and what is the purpose? The only possible solution I can come up with is that this is a practice race during the Le Mans test week, or in the days leading up to Le Mans 24 proper.
http://youtu.be/grDe7gi5pQI?t=3m23s