No, it should perform similarly. The typical heresy networks provide only low pass filters for the mids, relying on the acoustic roll off for the mid to tweet crossover. The ti diaphragms naturally extend higher, requiring the bandpass filter he referred to.
I have no idea if the kp201 have the ti or phenolic mids and corresponding networks. Seeing that they were owned by a church rather than some Klipsch nut who modded them, they probably have the correct driver/network combo. I say plug and play and see how it works. Should be essentially similar to the HIII, a good match for your fII (gems of the extended Heritage line IMO).
Don't be afraid to apply a bit of a downsloping house curve if you can, I think you would like it.