You have a fair chance, but not good. Even if an extra coach is added, if there are no cancellations on RAC, then your RAC numbers would still be on the RAC since the extra coach can accommodate only 72 passengers, of which if RAC is to be provided, then the number of confirmed passengers would come down to 64 I think.... somebody else perhaps can provide a more precise reply to this. This is my view.
Good wishes.