Don't forget that Wyer was Team Manager of Aston Martin (I wonder what happened to them) in the 1950s, and joined Ford for the GT40 project, leaving when they moved to the US to ensure "an American win", as the GT40, even the MkII was seen as British.
In 1967 he ran the GT40 based Mirage, with 5.7 litre engine, and slippery, carbon reinforced body. I'm sure it was the light blue. With the 3 litre prototype limit in 1968, he went back to GT40s, which were light blue, and played with a 3 litre BRM engined special, also called a Mirage, until Porsche came along.
I'm sure these were all the same colour, and darker the the latest AMR powder blue, but I have a faint recollection that they did start with the normal darker blue but quickly gave up because the didn't like it.