Club Motorsport are of the same opinion, just had an email about it:
"Clubmotorsport Le Mans 2007 - A.C.O. announce provisional dates.
The Race Authority have now announced provision dates as follows:
2007 Le Mans 24 hour - 16/17 June
French Moto GP, Le Mans - 30th May"
This is direct from their email to me.
Only, I am not sure why these nice people have told me...
I suppose the ACO need a fortnight or so to get up all the bits of dropped Motorcycles and allow for practice sessions too.

bill