As Matt said there is some distortion in the FK402. The display inside for the autoexposure is also more basic, only a dot for correct exposure and a single up or down arrow for over/under. There is also no choosing between spot or average (or auto). Despite all this at still works ok.
As far as I know the sport finder was also part of the waist level finder, which came with a mask roughly frame for different lenses.
I have a Pro TL for sale with one of each of the prisms if you are interested. http://www.apug.org/forums/forum379/...em-lenses.html