Jason

Those are later HZ DX5. Release until at least July 1978 are Bright Blue/Blue Green/Dark Blue.

The Dark blue/mid blue/light blue as quoted in the 1980 parts catalogue must have been introduced after July 1978, my guess is around 11/78 when the A632 colour chart was released. I do remember either yourself or Fletch telling me the DX5's reversed at some stage and this is probably when it happened. I don't know if the change would have happened earlier or later than the paint line changes. If you really want to narrow it down I can have a look and see when the new colours start to appear on vehicles. HZ ordering procedure appears to add all the new colour & trim combos in 10/78.