What Jordan said, modification will be needed .
For example, when I installed a real E2 grip to fit on a TM/KJW type of frame, I had to reduce the diameter of the grip screw bushings to fit the holes on the inside of the grip.

EDIT -
I was also able to use the real decocking lever( top one) that came with the grip kit. It doesn't extend as far into the frame as the TM lever, but it does work.