when I export my archicad plans to DWG I get an issue with my zonestamp. When I double click the zonestamp in archciad to enter the Enhanced Attribute Editor > Properties the color of the zonestamp is set to white but I want it to be By Layer. Can this be changed in the export from archicad?
1 - In your DWG translator you can choose to set all elements to be published by layer (Settings > Attributes > Pens and Colors > "Set all Elements' Colors and Lineweights to "BYLAYER"").
But you might not want to do that for "everything" so you can try my second option below.
2 - You can "dedicate" one of your Archicad pen colors only to Zone Stamps and then use "Pen-color conversion" table in your translator. For example Archicad pen "255" to Autocad pen "256" (BY LAYER). This works only on that selected Archicad pen and does not mess with the rest.