Sony and MS have been promoting their exclusive racing franchises at LeMans since 2007. I would expect both to continue. I was at that 24hr event in 2007 and both had cockpit booths in the 'inner village' along with sponsorships either on the track or on cars.
Personally I love the competition. Both game franchises are great and both seem to be secretly after each others space. Before Peugeot had Playstation logos on their 908s, they wore xbox 360 logos. Also the first chicane down the Mulsanne Straight changed from the PlayStation chicane to Forza Motorsport chicane.
As a side note, if anyone ever has the chance to experience this epic 24hr race, GO!!!! You will love it.