Interesting observation. But I don't know why they would add additional paint to those parts of the rangefinder after production. Seems kinda random. I don't think those photos definitively prove the absence of weathering in those areas, between the lighting and the image quality it's not clear enough to say. Not to mention the Blu-rays have heavy noise reduction.
Also if you're comparing the helmet in it's "present" condition to production images, you need to distinguish between weathering and damage/markings that the helmet has taken on in the subsequent years. Like the blue sharpie, visor repair, gelcoat cracks, glue marks, etc.. To me those dark splotches are distinct from the orange rust paint that we see spattered across that side of the helmet. It looks more like grime that has accumulated, possibly some adhesive residue that caused that blackish buildup.
That's just my interpretation, I could be wrong. Maybe during the filming of ROTJ SE someone thought that area looked too clean and shiny so they dabbed some paint on there.
