Cuprinol treatment of the ash frame was standard from 1986 IIRC. It was optional for a few years before - our first Morgan was from 1985 and the original build sheet showed that Cuprinol had been applied at extra cost.
I don’t know when it became standard to remove the wings before painting the car. Again, our 1985 car had wing beading fitted - which was optional and ensured that the wings were removed for painting. Any car without wing beading, of any vintage, could have been painted with the wings on - which leads to corrosion issues.
My car was built in May 1986 and wasn't Cuprinol dipped. It did have wing beading fitted, but was originally painted with the wings on so the beading was painted over.
