Randy, when you associate WTParts to CAD Documents and build them the attributes that are on the CAD Doc are pushed to the Part (assuming the association type is one that will push attributes over, such as Owner or Contributing Content). The attributes that are pushed over are controlled by the preferences under Site > Utilities > EPM Service Preferences > Build Service Preferences:
OOTB it will publish all CAD Doc attributes on the Part. As long as the parameter within Creo (or NX) has been designated and mapped to a Windchill IBA on the CAD Doc type that parameter value can be pushed to the Windchill Part.
