Thanks Jon. From what little info I have gathered on these wheels (I believe they were called Ansen Apollo), they are quite rare, having only been produced for a short period of time. One forum I visited said only 120 sets were made, but I don't know how correct this is.
Why do you think they would have fit these wheels to the Camaro for this event, then reverted to the rally wheels? From my online searching, the widest set I have seen has only been 6" wide, so maybe I just answered my own question.