The vin car is probably destroyed and your car is a junkyard find with no title.So during converting back to a street car he put the dash from the 74 in your 73(HIGHLY ILLEGAL).Possible jail time if they don't believe you.This is one theory,the next theory is that the back end was swapped to the 70-73 style and the trunk lid was changed also and you actually have a 74 converted.I would go with theory number two and let it rideeeeeeee.