...and does it matter in a significant functional way?

I took notice of my RB that I've not used since the fall in favor of my older so designated beater (but not so anymore for a case of upgraditus) Anyway, I realized that the faceplates on my brifters where gone...I guess they popped out as the result of a few minor spills I took.

I assume they're there for a reason other than Shimano advertising, offering some protection from the elements. Am I correct? Should I go scouring the bike shop junk piles for replacements? Should I get out the electrical tape? Or should I not care at all?