When converted to a ctb, pcp files do NOT involve the colour. You will need to set this to black. Here's an explanation...
When exporting a Revit file to AutoCAD a 'pcp' file is created in the same folder of the 'dwg'. This file is intended to duplicate the lineweight of the Revit file in the AutoCAD file. You will need to convert the pcp file to a ctb file in AutoCAD.
-You can do this by using the Print-Manage Plot Styles-Add a Plot Style Wizard.
-The Wizard will prompt you for a pcp file as you go.
-Before you finish click on the Plot Style Table Editor button.
-Then go to Form View. Select all of the colours (listed as Plot styles). Then change their property colour to black.