Does the Bumper Launcher Kit (BLK) fit the PASCO track?

Yes, Bumper and Launcher Kit, order code BLK, $89 will fit PASCO tracks.

As shipped, the mounting screws and nuts are positioned to fit the Vernier track. You'll see a secondary pair of holes adjacent to the mounting screws. Move the 1/4-20 nylon screws to the more widely-spaced pair of holes, and the height of the assembly will then be correct for the PASCO track.

You'll need to rearrange the bumper storage locations, putting the magnet discs in the upper storage holes, so that there is room for the nylon screws.