Luckily.. I left mine on because one day my younger brother, who was an absolute moron for doing this, blew a candle out so hard, wax went all over the front of my RC-25. Good thing the grille (dust cover) was on!
btw. If anyone has a grille for the RC-25 and wouldn't mind selling it, I'd be interested. I contacted Klipsch, but a new grille will cost about $60, so I opted to hold of for a bit in hopes of finding someone that would sell me theirs.