Can be? I'd go a step further and say, should be! Having all 5 speakers acoustically matched is a good thing. For my home theater I bought three pairs of identical speakers, so that I have a 6.1 array, right front, center, left front, left rear, center rear, and right rear all the same.Yes, matching speakers can be used for the front and rears. Can't say if the Klipsch speakers will sound better than your current speakers. Amazon offers free returns, so it can't hurt to give them a try.
Wayne A. Pflughaupt