When converting a MacWrite II document that has a date variable inserted, regardless of the the preference setting of the MacWrite II document, the date will update with the current date that is on the system.
The MacWrite II translator seems to ignore the preference setting for "Never Update" embedded in the MacWrite II document.
This is is an issue if you wish to refer back to the date. The only work around at this time is to open the document in MacWrite II and copy it then paste it into ClarisWorks.