IMO we have not seen any real indication of what the C8 flags will look like. We saw a Keyfob that is obviously the C8 fob, but it looks to me like the emblem on the fob is photoshopped. There is a sister car key fob that looks exactly like the Cadillac emblem indented into that fob, but the vette's fob looks funny.
These were circulating around but the new Cad V8 will be called the Blackwing (remember the Northstar DOHC V8?) so, IMO, this emblem is more likely to be associated with that engine.