No protocol. Each is the same tartan woven in different shades. Rest assured that Ancient MacKenzie is the same as Modern MacKenzie, mate.

One thing to consider is that many of the so - called "ancient" colour palette days to no later than the early 1900s. The "modern" colour palette is actually older. They date to Victorian times.

Prior to the early 1800s very few tartans that we recognise today even existed!