In case you are interested in seeing old paint chips of Cape Maroon, a few are linked-to near the top of the Tech Tip for Paint Codes 47-55 Advance-Design Trucks:

Acme - PROXLIN chip

Ditzler/PPG chip

At the bottom of that Tech Tip is information on how to contact PPG. You might get lucky and they might give you the name of a modern "offset" code/name/formula.

As you most likely know, old chips (and old trucks, and scanned old chips, and computer screens) would display colors that might not be true to the original non-oxidized, non-aged, paint color.