Yes, because you have to cut it to fit.
Remove the window
Slip one end of the channel into frame and slide it under the clip at the bottom.
work your way around pressing it firmly into the track.
Cut the other end to to fit and slide it under the other clip.
Drill several holes through the channel and frame tap size for #4 screws. ( I usually go back and open the hole in the channel 1 drill size larger so the flat head screws sit down tight)
Install the flat head sheet metal screws.
