Yes. You are correct in your first paragraph above, and if there is a new
LaserWriter/Laser Prep file introduced you should be able to upgrade to
that driver with no other system upgrade, unless it was so specified.
There was an upgraded Print Monitor with the 6.x drivers. Version 1.3 was
distributed with the System 6.0.5 suite of diskettes while version 1.2 was
distributed with the System 6.0.4 suite of diskettes. The 1.3 version
would probably contain the enhancements necessary for use with any of the
current printer drivers.