I think you are right, if some one bought the fiberglass group4 kit I do not think they could get the flares on the backwards. What I think happened was that when they made the mold they made them backwards. On the factory group4 the flares are wider in the front and narrower behind the wheel. But when you look at the car it is narrower in front and gets wider in back. So at some point someone thought the flares should go that way. By the way this was 8 years ago and may have been fixed back then. I really do not know.
BTW I love all the metal work you have done. The cars is amazing.