There is a wide range of shades between the pale blue and lilac blue that I have listed. It seems that the early models were mostly shades of pale blue, including a quite bright baby blue and sky blue, whereas later editions were predominantly lilac blue or similar.
Free spinning wheels would have been introduced on this model by 1962, possibly earlier and may be found with base type 1b, although I have seen any yet. In 1966 the cast, spoke effect type will have been fitted and shortly afterwards a switch to the type 2 body casting would have been made. This will have resulted in very short production periods for some editions.