That could be an original fork, the crown looks right for a Super Sport / Sports Tourer / Superior.

The 600 brakes would be too short in the rear. They might look nicer but wouldn't be likely to work any better or be easier to adjust than the Universals.

The Kool Stops should work well but it looks like you might have Matthauser pads on there now. If so they should work just as well. They may only need to be cleaned up a bit.