Most people like their glossy white rubber hand guards, because they're sooo shiny!
But if you'd like them more matt (= screen accurate) looking, you have 2 possibilites:
1)temporarily: Baby powder. Spread some on the hand guards and you get a semi gloss
2) permanently: Put some Zippo lighter fluid on a cotton ball (pad) and wipe it across your hand guard to tone the gloss down until you're satisfied.
I hope that helps!
Karin