Colors are odd things. But thankfully there is solid evidence for the more puprle tone to R2 in ANH. I took this pic at the costume exhibit in Denver. At least one of the R2 costumes/props, was very purple, as you can see from the eye surround in the middle.

I took a lot of pictures with color correcting the films in mind.

Not a lot from ANH, but a few. And they put forward a single costume as representative while one exhibit showed just how many version of Obi-wan’s costumer there were for ROTS. So while I think Red Leader only had the one helmet, there were many R2 costumes/props and I’m sure multiple version of Ben’s costume and I think I heard there were 2 for Chewy.