It would be neat to know the cars numbers so we can figure out its approximate build date. If you don't want to share the numbers on a public forum you could go to https://www.healeydata.com/ and use the database to get a good idea when this car was built, assuming it has the original numbers.
I had a thread on this about two years ago. I built three late BJ8 engines, all three had a blue color underneath the healey green. Never got a satisfactory answer on why.View attachment 51954