I've just had a quick look in Doug Nye's Cooper masterpiece to see if I could resolve this, but it is indeed a complex matter.When its racing days were over, the Tom Kyffin car was converted back to single-seat F2 form for historic racing, and the body fitted eventually onto one of the road/race early Cooper-MG chassis, and this is what exists in the US today. Which is presumably what the puzzle car is, except it has portholes in the bonnet sides, and Kyffin's car didn't have these. Maybe they were done for aesthetic purposes.