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.
I don't think this is quite right: the cars that were painted with the wings on had beading but everything was assembled before they were painted, so that the tell-tale sign is that the beading is also painted.
