Below are pictures of my RS Props ANH Jim Dowdall signature edition, RS Props ESB Stunt, Anovos ANH, and an Anovos ANH converted to ESB.
The Jim Dowdall is several years old. I bought it from a fan so I do not know the details about it's construction. I'm not sure if it is ABS or PVC, but it is noticeably shinier than the RS ESB which I got within the last few months. The cap of my RS ESB Stunt and RS ANH Hero are both duller than the faceplate on the same helmet.
I purchased the Anovos converted to ESB from a fan, so I did not do it myself. From what I understand the frown and stickers were redone and the helmet was polished. This is the most shiny of any of these helmets. The Anovos helmets are ABS. As long as you don't have weathering to worry about, polishing should work fine to make the helmet more shiny. Although I'm not sure about polishing over the bumps on the RS.
RS Props ANH Jim Dowdall signature edition
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RS Props ESB Stunt
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Anovos ANH
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Anovos ANH converted to ESB
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