You don't need to rebuild the pages, but you will need to inspect each of the server behaviors to have the code regenerated for data bridge.
I would make a site backup first,
then open the first page, for examples sake lets say it is an insert page. On the server behaviors panel, double click the Insert Record server behavior then click ok to have the code regenerated.
Re inspecting the server behavior may leave being a reference to the older Data Assist helper pages:
<?php require_once("WA_DataAssist/WA_AppBuilder_PHP.php"); ?>
that you will need to delete manually.
You will need to repeat this for each of the pages.